Showing papers by "Aix-Marseille University published in 1994"
TL;DR: A role of FDB in the fine-tuning of postural adjustment during forward leaning, and a weight-supporting role of Sol are suggested in the common range of inclination.
259 citations
TL;DR: In this article, the authors used a Fisherian distribution characteristic of paleosecular variation (PSV) and a uniform distribution representing transitional data resulting from reversals and excursions of the geomagnetic field to determine the most precise value of the angular standard deviation (ASD) characteristic of PSV.
249 citations
TL;DR: It is demonstrated that reduced binding actually corresponds to decreased expression of the gene coding for the D2 receptor in the pituitary from bromocriptine-resistant patients, as shown by 4-fold lower levels of the corresponding mRNAs compared to those coding for actin.
Abstract: Bromocriptine or other dopamine agonists are usually effective for the treatment of prolactin-secreting adenomas. Five to 18% of prolactinomas, however, do not respond to such therapy. We have shown previously that such resistance to bromocriptine correlates with reduced binding to the D2 receptor subtype of dopamine, the major PRL inhibiting factor. In the present work, we demonstrated that reduced binding actually corresponds to decreased expression of the gene coding for the D2 receptor in the pituitary from bromocriptine-resistant patients, as shown by 4-fold lower levels of the corresponding mRNAs compared to those coding for actin. The existence of two D2 receptor isoforms, D2S and D2L generated by alternative splicing, has been described in several tissues, including the pituitary. Both are negatively coupled to adenylyl cyclase and inhibit prolactin secretion, but, in addition, the shortest one (D2S) is more efficiently coupled to phospholipase C. Consequently, we also investigated whether expression of a particular D2 receptor isoform was preferentially affected in resistant adenomas. The proportion of messengers corresponding to the short receptor isoform (D2S) was lower in resistant compared to responsive adenomas: D2S/D2L = 0.74 ± 0.08 and 1.00 ± 0.07, respectively. In parallel, much lower levels of D2 receptor mRNAs were found in growth hormone-secreting adenomas, with a D2S/D2L ratio comparable to those of both normal human pituitary and bromocriptine-sensitive prolactinomas (1.05 ± 0.11). Thus, resistance to bromocriptine therapy seems to involve defects in D2 dopamine receptor expression and possibly in posttranscriptional splicing.
166 citations
TL;DR: It has been found that the accumulated sulfide is oxidized not only by the phototrophic bacteria in the sulfide oxidation zone but also by the oxygen produced by the cyanobacteria which are able to photosynthesize in the presence of sulfide.
160 citations
156 citations
TL;DR: RFLP analysis of PCR-amplified genes was used to study spotted fever group (SFG) rickettsiae, and the proposed simplified model of identification may be useful in studying the geographical distributions of SFG ricksettsiae.
Abstract: Restriction fragment length polymorphism (RFLP) analysis of PCR-amplified genes was used to study spotted fever group (SFG) rickettsiae, extending the previous work of Regnery et al. (R.L. Regnery, C.L. Spruill, and B.D. Plikaytis, J. Bacteriol. 173:1576-1589, 1991). Twenty-six strains of SFG rickettsia were studied, including several recognized species which have never been studied (R. parkeri, R. helvetica, and R. japonica) as well as strains which are not currently classified. Two previously used primer pairs derived from the R. prowazekii citrate syntase gene and the R. rickettsii 190-kDa protein antigen gene were studied, as were primer pairs obtained from the R. rickettsii 120-kDa protein antigen gene. By using three amplifications and three enzyme digestions, it was possible to differentiate between almost all of the known SFG rickettsia species and to differentiate between several strains of the R. conorii complex. Two human pathogens, "R. africae" and the Israeli tick typhus rickettsia, were first separated by using BG-12 pair primer amplification and then RsaI restriction endonuclease digestion. The proposed simplified model of identification may be useful in studying the geographical distributions of SFG rickettsiae.
127 citations
TL;DR: In this article, the lattice and sub-boundary diffusion coefficients of aluminium self-diffusion were measured in single crystals of α-Al2O3 in the temperature range 1540-1697°C using 26Al as a radioactive tracer.
Abstract: Aluminium self-diffusion has been measured in single crystals of α-Al2O3 in the temperature range 1540–1697°C using 26Al as a radioactive tracer. Two diffusion mechanisms are involved: a lattice diffusion mechanism and a subboundary mechanism. Lattice and subboundary diffusion coefficients obey equations and respectively. The results show that lattice diffusion coefficients of aluminium are much lower than those determined earlier. The comparison with oxygen diffusion determined by other workers for the same specimens shows that oxygen and aluminium diffusion coefficients are of the same order of magnitude in the lattice but that aluminium diffusion coefficients are greater than oxygen diffusion coefficients in subboundaries.
117 citations
TL;DR: The Guerrero terrane, composed of Late Jurassic-Early Cretaceous sequences, extends from Baja California to Acapulco and is considered to be coeval with the late Mesozoic igneous and sedimentary arc sequences of the Greater Antilles, the West Indies, Venezuela and the Western Cordillera of Colombia as discussed by the authors.
111 citations
TL;DR: In this paper, geomorphological, marine biological and radiometric data in combination with earlier reports reveal that the M, =7.2, 1953 Cephalonia earthquake, the most destructive but least studied earthquake in Greece this century, was associated with a 0.3-0.7m quasi-rigid-body uplift and westward tilting of the central part of the island.
Abstract: SUMMARY Geomorphological, marine biological and radiometric data in combination with earlier reports reveal that the M, =7.2, 1953 Cephalonia earthquake, the most destructive but least studied earthquake in Greece this century, was associated with a 0.3-0.7m quasi-rigid-body uplift and westward tilting of the central part of the island. Another palaeoseismic event, around 1500 yr BP, associated with coastal uplifts was also identified. Structural data indicate that the 1953 uplift is bounded by two subparallel, east-dipping major reverse faults and corresponds to a piston-like motion. This structurally unusual pattern of seismic deformation is detached from the deformation of the basement (conspicuously a thrust) and different from the long-term deformation pattern of the area; it is probably due to the particularities of salt tectonics: a -1500m thick salt layer acts as a regional dCcollement, while thinner layers are sandwiched between the carbonate thrust sheets that compose the overburden and reduce their friction during fault movement. This crustal anisotropy is responsible for the observed anomalous attenuation of seismic waves during the 1953 and historical earthquakes. The 1953 seismic surface deformation mimics long-term halotectonic patterns, but is not directly indicative of the regional stress-field, for it reflects uplift-induced stresses only.
96 citations
TL;DR: All the ceramic powders tested here and therefore the corresponding bulk ceramics or ceramic coatings do not induce any cytotoxic effect and the correlation which has been previously observed between cytotoxicity-cell culture response and blood haemolysis for polymers has not been established.
Abstract: General cytotoxicity was assayed for ceramic (Al2O3, ZrO2/Y2O3, AIN, B4C, BN, SiC, Si3N4, TiB4, TiC, TiN) diamond and graphite powders, using 3T3 Balb/c permanent cell lines. Neutral red test was carried out in order to establish cell viability. Further investigations were undertaken on human differentiated cells (human umbilical venous endothelial cells): cell behaviour (MTT assay, total cell protein content) and differentiation (immunofluorescence) were studied. In both cases, no cytotoxic effect has been noticed. All the impurities contained at low concentration in these powders do not seem to present any effect. The correlation which has been previously observed between cytotoxicity-cell culture response and blood haemolysis for polymers has not been established here for ceramic powders. We conclude that all the ceramic powders tested here and therefore the corresponding bulk ceramics or ceramic coatings do not induce any cytotoxic effect.
88 citations
TL;DR: In purified T lymphocytes induced to proliferate by the combined action of monoclonal antibodies directed against the CD2 and CD28 adhesion molecules, Ku p70 and p80 mRNA steady-state levels increased as soon as 6 h after activation and lasted at least 72 h.
Abstract: Ku protein is a relatively abundant DNA-binding nuclear protein complex composed of two polypeptide subunits, p70 and p80. Ku has been recently identified as the regulatory component of the DNA-dependent protein kinase that phosphorylates RNA polymerase II. To further characterize in vivo regulation of Ku protein, we studied the expression of the transcripts coding for the Ku p70 and p80 subunits in different human cell lines and normal tissues by Northern blot hybridization, using specific cDNA probes. The expression level of both genes was approximately 10-fold higher in established cell lines than in normal tissues. However, mRNA expression levels in permanent cell lines correlated more strongly with their proliferative state than with their level of malignant transformation. In purified T lymphocytes induced to proliferate by the combined action of monoclonal antibodies directed against the CD2 and CD28 adhesion molecules, Ku p70 and p80 mRNA steady-state levels increased as soon as 6 h after activation and lasted at least 72 h. The human genes coding for the Ku p70 and p80 subunits were localized by cytogenetic mapping, using fluorescence in situ hybridization, to 22q13 and 2q33-->q35, respectively.
TL;DR: Suramin, a polysulfonyl naphtylurea known to inhibit retroviral reverse transcriptases in vitro, blocks HIV-1 infection in HT-29 cells because it binds to the V3 domain of gp120 and hence prevents the interaction between gp 120 and the GalCer receptor.
TL;DR: In this article, a model involving two reservoirs located at different depths and periodically connected is proposed to explain the petrography of the lavas; this hypothesis is in accordance with geophysical data.
Abstract: Three major phases are distinguished during the growth of Nyiragongo, an active volcano at the western limit of the Virunga Range, Zaire Lavas erupted during phase 1 are strongly undersaturated melilitites characterized by the presence of kalsilite phenocrysts, perovskite, and the abundance of calcite in the matrix Such lavas crop out mainly on the inner crater wall and progressively evolve toward more aphyric melilite nephelinites well represented on the flanks of the volcano Adventive vents lying at the base of the cone developed along radial fracture systems and erupted olivine and/or clinopyroxene – rich melilitites or nephelinites Stage 2 lavas are melilite-free nephelinites Clinopyroxene is the main phenocryst and feldspathoids are abundant in the lavas exposed on the crater wall These flows result from periodic overflowing of a magma column from an open crater Extensive fissure flows which erupted from the base of the cone at the end of this stage are related to widespread draining out of magma which in turn induces the formation of the summit pit crater Magmas erupted during stage 3 are relatively aphyric melilite nephelinites and the main volcanological characteristic is the permanent lava lake observed into the pit crater until the 1977 eruption Fluctuations of the level of the lava lake was responsible for the development of the inner terraces Periodic overflowing of the lava lake from the central pit formed the nepheline aggregate lava flows Petrography and major element geochemistry allow the determination of the principal petrogenetic processes Melilitites and nephelinites erupted from the summit crater are lavas derived, via clinopyroxene fractionation, from a more primitive melt The abundance of feldspathoids in these lavas is in keeping with nepheline flotation Aphyric melilite nephelinites covering the flanks and the extensive fissure flows have a homogeneous chemical composition; rocks from the historical lava lake are slightly more evolved All these lavas differentiated in a shallow reservoir Lavas erupted from the parasitic vents are mainly olivine and/or clinopyroxene-phyric rocks Rushayite and picrites from Muja cone are peculiar high-magnesium lavas resulting from the addition of olivine xenocrysts to melilitic or nephelinitic melts Fluid and melt inclusions in olivine and clinopyroxene phenocrysts indicate a crystallization depth of 10–14 km A model involving two reservoirs located at different depths and periodically connected is proposed to explain the petrography of the lavas; this hypothesis is in accordance with geophysical data
TL;DR: The results suggest that the locomotor response to MK-801 is dependent on an interaction between dopaminergic and excitatory amino acid transmission occurring postsynaptically rather than presynaptically in the ventral striatum.
TL;DR: It is suggested that overexpression of utrophin is not enough to explain the stability of regenerated fibers in mdx mice, and the pathological process became stable in all muscle types (except the diaphragm), with greater utphin expression in the soleus.
TL;DR: The results indicate that the expression of the beta 2 chain gene is tightly regulated in normal human tissues and in disease.
TL;DR: Surgical reconstruction of the superior vena cava with an ePTFE prosthesis provided immediate and long-term relief of symptoms of superior vene cava obstruction with a low surgical morbidity, even In patients with unresectable malignancy.
TL;DR: Pigments of vanadium dioxide VO 2 were inserted in a polymeric coating to analyze the optical thermochromic behavior linked with the semiconductor-metal first-order transition at 341 K.
TL;DR: It emerged that one set of hydrocarbons, which were usually present in rather small proportions and included all the families that constitute this species' chemical signature, was characteristically associated with workers from monogynous colonies and can be said to have characterized the digynous and trigynous colonies.
Abstract: The results of laboratory experiments carried out with both monogynous and artificially polygynousMessor barbarus ant colonies (which under natural conditions are always monogynous) have shown that the workers belonging to monogynous colonies were able to discriminate between intruders from other monogynous colonies and those from polygynous (di- and trigynous) ones. What mechanisms are involved in this discriminatory ability? Since differences in the relative proportions of the hydrocarbons they carry are known to convey complex messages that are used for recognition purposes, it was proposed here to investigate whether there existed any differences in the proportions of the various hydrocarbons carried by the diverse categories of intruders tested in our experiments. It emerged that one set of hydrocarbons, which were usually present in rather small proportions and included all the families that constitute this species' chemical signature (n-alkanes, mono-, di-, and trimethylalkanes), was characteristically associated with workers from monogynous colonies. Another set of hydrocarbons, which included some of the above components, mostly in larger relative proportions, can be said to have characterized the digynous and trigynous colonies.
TL;DR: In this article, the decays into hadrons and charged leptons have been analysed to give values for the cross sections and leptonic forward-backward asymmetries which are significantly improved with respect to those previously published by the DELPHI collaboration.
Journal Article•
TL;DR: Between 1980 and 1991, 13 of 1312 carotid artery reconstructions were performed for aneurysms of the extracranial internal carotids, with a mean follow-up of 46 (4-126) months.
TL;DR: Several E-W profiles of Bouguer anomalies across the Precambrian basement were inverted by applying a linearized inversion procedure in the spectral domain and using a simplified two-layer model with a crust-upper mantle interface of constant density contrast.
Abstract: Several E-W profiles of Bouguer anomalies across the Precambrian basement were inverted by applying a linearized inversion procedure in the spectral domain and using a simplified two-layer model with a crust-upper mantle interface of constant density contrast From these inverted profiles, a contour map of Moho topography has been constructed which covers the area of exposed Precambrian basement in the eastern and central parts of the island Such imaging of the Moho depth in particular exhibits a N20°E-trending zone of substantially thinned crust along the axis of the island This parallels the east coast margin which resulted from the northward motion of India relative to Madagascar in the Upper Cretaceous From combined analysis of geological, tectonic and metamorphic observations, this prominent crustal feature in the Precambrian basement of Madagascar is interpreted as the relic of continental lithospheric extension and thinning possibly related to Panafrican collapse tectonics on the eastern edge of the Mozambique belt This extensional feature would have been reactivated only in part during the rifting and dislocation stages of the Madagascar and India continental blocks as evidenced by an axis of Cretaceous volcanism emphasized by the Ankaratra and Itasy massifs Final separation nevertheless occurred further east, at the site of the east coast margin
TL;DR: The results suggest that the level of the striatal dopaminergic activity may play a critical role in regulating the glutamate transmission via the N-methyl-D-aspartate receptors during the performance of complex sensorimotor tasks of this kind.
TL;DR: In this article, the DELPHI experiment was used to reconstruct J/psi mesons from their decay to mu(+)mu(-) and e(+)e(-), using the data collected by the Delphi experiment during 1991 and 1992.
Journal Article•
TL;DR: It has been concluded that the day +6 administration of rhG-CSF gives the same clinical benefit as day +1 administration with consequent cost reductions.
Abstract: Recombinant granulocyte colony-stimulating factor (rhG-CSF) has been shown to hasten granulocyte recovery after autologous BMT. In current protocols, rhG-CSF treatment starts 1 day after BM reinfusion. Our study retrospectively examined the effects on haematological recovery of a day 6 delayed administration. Seventy-eight patients receiving autologous BMT for malignant lymphoma (21 non-Hodgkin's lymphoma and 9 Hodgkin's disease) or solid tumors (33 breast carcinoma and 5 ovarian carcinoma) were split up into three study groups. Two groups receiving a 5 micrograms/kg/day of rhG-CSF starting either 1 day (day +1 group, n = 25 patients) or 6 days (day +6 group, n = 24 patients) after BM reinfusion were compared with 29 historical control patients. Granulocyte recovery to 0.5 x 10(9)/l was 12 days in day +6 and day +1 groups versus 16 days in control group (p < 0.005) without any difference in other hematological parameters, infectious complications or length of hospitalisation between the three groups. The day +6 administration allows elimination of a median of 7 days rhG-CSF. It has been concluded that the day +6 administration gives the same clinical benefit as day +1 administration with consequent cost reductions.
TL;DR: expression of the α3‐subunit isoform in dog heart membranes was consistent with a high affinity digitoxigenin‐sensitive class of Na,K‐ATPase, which is the first report of the catalytic characteristics of theα3 subunit isoenzyme in canine cardiac plasma membranes.
TL;DR: In this paper, the effects of the angle between the two branches of the junction and the air-flow rate upon the structure flow are analyzed, for both forced and mixed convection cases.
TL;DR: The changes related to either the dizocilpine maleate treatment or the 6-hydroxydopamine-induced lesion totally disappeared, so that the number and staining intensity of neuropeptide Y-immunoreactive neurons in that condition did not differ from control values.
TL;DR: The main results supported the view that, in the caudal SC of newts, Tn, synthesized by radial ependymoglial cells, was similarly expressed during regeneration as well as larval development, and exhibited a sustained high accumulation level in the adult SC.
Abstract: Tenascin (Tn) protein and transcripts were analyzed in developing, adult and regenerating caudal spinal cord (SC) of Pleurodeles waltl. A polyclonal antibody (PAb) against Xenopus Tn and a newt Tn cDNA probe were used. In Western blots, anti-Tn PAb recognized Tn polypeptides of 200-220 kDa in tail regenerate extracts, but also the homolog of Tn/Cytotactin/J1 in brain and SC of adult newt. Immunofluorescence studies showed some reactivity around ependymoglial cells and strong labeling in the nervous tracts, in the developing as well as in the regenerating SC or adult SC. Immunogold electron microscopy revealed the presence of Tn throughout the ependymoglial cells, particularly near and along the plasma membrane of radial processes surrounding axons, especially growth cones. Tn could be more precisely found within rough endoplasmic reticulum and Golgi structures, or again in the surrounding extracellular space. This suggested that Tn was at least produced by radial glial profiles forming axonal compartments in which axons grew. Using the DNA probe for Tn, expression of Tn mRNA was also examined by Northern blot and RNAase protection analyses and by in situ hybridization, respectively. The levels of transcripts, barely detectable in adult tail, increased in regenerates from 3 days through 4-8 weeks post-amputation. In situ Tn mRNA were mainly localized in the mesenchyme, especially at the epithelial-mesenchymal interface, and in the developing cartilage, at the early regeneration stages, whereas high amounts of transcripts were seen not only at these stages, but also later, in the regenerating SC. Our main results supported the view that, in the caudal SC of newts, Tn, synthesized by radial ependymoglial cells, was similarly expressed during regeneration as well as larval development, and exhibited a sustained high accumulation level in the adult SC. On the basis of the multifunctional properties of Tn, the putative roles played by Tn as a substrate for neuronal pathfinding and boundary shaping were discussed.