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Showing papers by "University of Florence published in 1993"


Journal ArticleDOI
09 Sep 1993-Nature
TL;DR: In this article, it was shown that the magnetization of the Mn12 cluster is highly anisotropic and the magnetisation relaxation time becomes very long below a temperature of 4 K, giving rise to pronounced hysteresis.
Abstract: MAGNETIC materials of mesoscopic dimensions (a few to many thousands of atoms) may exhibit novel and useful properties such as giant magnetostriction, magnetoresistivity and magnetocaloric effects1–4. Such materials also allow one to study the transition from molecular to bulk-like magnetic behaviour. One approach for preparing mesoscopic magnetic materials is to fragment bulk ferromagnets; a more controllable method is to take a 'bottom-up' approach, using chemistry to grow well defined clusters of metal ions5,6. Lis7 has described a twelve-ion manganese cluster in which eight of the Mn ions are in the +3 oxidation state (spin S=2) and four are in the +4 state (S=3/2). These ions are magnetically coupled to give an S=10 ground state8, giving rise to unusual magnetic relaxation properties8,9. Here we report that the magnetization of the Mn12 cluster is highly anisotropic and that the magnetization relaxation time becomes very long below a temperature of 4 K, giving rise to pronounced hysteresis. This behaviour is not, however, strictly analogous to that of a bulk ferromagnet, in which magnetization hysteresis results from the motion of domain walls. In principle, a bistable magnetic unit of this sort could act as a data storage device.

3,327 citations


Journal ArticleDOI
TL;DR: IL-12 and CD16+ cells appear to have inhibitory effects on the development of IL-4-producing cells and to play an inductive role in promoting Th1-like responses.
Abstract: The effects exerted on the in vitro development of antigen-specific T cell lines and T cell clones by addition or neutralization of interleukin 12 (IL-12) in lymphocyte bulk culture were examined. T cell lines specific for Dermatophagoides pteronyssinus group I (Der p I) derived in the presence of IL-12 exhibited reduced ability to produce IL-4 and increased ability to produce interferon gamma (IFN-gamma), and developed into Der p I-specific CD4+ T cell clones showing a T helper type 0 (Th0)- or Th1-, instead of Th2-, like cytokine profile. In contrast, purified protein derivative (PPD)-specific T cell lines derived in the presence of anti-IL-12 antibody exhibited an increased ability to produce IL-4 and developed into PPD-specific CD4+ T cell clones showing a Th0-, instead of Th1-, like profile. The influence of IL-12 on the cytokine secretion profile of Der p I-specific T cell lines was not prevented by addition to lymphocyte bulk cultures of anti-IFN-gamma antibody, but could be at least partially inhibited by the removal from bulk cultures of CD16+ cells. Thus, IL-12 and CD16+ cells appear to have inhibitory effects on the development of IL-4-producing cells and to play an inductive role in promoting Th1-like responses.

1,700 citations


Journal Article
TL;DR: Data demonstrate that, unlike the murine system where IL-10 is a product of Th2 (but not Th1) cells and seems to mainly down-regulate the Th1 response, in the human system, IL- 10 is produced by, and down- Regulates the function of, both Th1 and Th2 cells.
Abstract: IL-10 gene transcription and IL-10 protein production was assessed in both type 1 (Th1) and type 2 (Th2) CD4+ human T cell clones by polymerase chain reaction and ELISA, respectively Although Th2 clones apparently showed higher IL-10 mRNA levels, IL-10 mRNA expression was consistently found in Th1 clones, as well Likewise, measurable IL-10 levels were found in the supernatants of both Th1 and Th2 clones The effect of human IL-10 (h-IL-10) and viral IL-10 (v-IL-10) on the proliferative response and cytokine production by Th1 and Th2 human clones was also investigated Addition in culture of h-IL-10 and v-IL-10 significantly reduced the proliferation of both Th1 and Th2 clones in response to the specific Ag and to PHA, but it had no inhibitory effect on the proliferative response of Th1 and Th2 clones to IL-2 h-IL-10 and v-IL-10 also inhibited the Ag-induced production of gamma-interferon (IFN-gamma) by Th1 clones and the production of IL-4 and IL-5 by Th2 clones, whereas they had no effect on the cytokine synthesis by the same clones stimulated with PMA plus anti-CD3 antibody Preincubation of APC, but not of clonal T blasts, with h-IL-10 resulted in the inhibition of Ag-induced proliferation of both Th1 and Th2 clones, supporting the view that h-IL-10 primarily affects APC These data demonstrate that, unlike the murine system where IL-10 is a product of Th2 (but not Th1) cells and seems to mainly down-regulate the Th1 response, in the human system, IL-10 is produced by, and down-regulates the function of, both Th1 and Th2 cells

975 citations


Journal ArticleDOI
TL;DR: In this paper, the authors provided a set of normative data on the Mini-Mental State Examination (MMSE) from a random sample of 906 normal, healthy subjects of both sexes, 20 to 79 years of age.
Abstract: We provide a set of normative data on the Mini‐Mental State Examination (MMSE) from a random sample of 906 normal, healthy subjects of both sexes, 20 to 79 years of age. Subjects were selected in six Italian cities and in the Republic of San Marino. Results show the significant influence of sociodemographic variables, such as age and education, on MMSE performance. We used Multiple Linear Regression Analyses to correct MMSE normative values for these demographic effects. The analyses allow us to specify cutoff scores for distinguishing “normal” performance from “borderline” and pathologic performance.

664 citations


Journal ArticleDOI
TL;DR: Serri et al. as mentioned in this paper proposed that the delamination and migration of the Adriatic continental lithosphere related to the di erention of the northern Apenninic arc magmatism can be explained by a geodynamic process which causes a variable amount of phlogopite through reaction between fluids and/or melts with the mantle.

445 citations


Journal ArticleDOI
01 Oct 1993-Blood
TL;DR: Results showed that bone marrow cell liquid cultures recovered from severely hypoxic day-5 liquid cultures showed the same day-7 colony-formation efficiency in semisolid culture (neutrophilic/monocytic colonies) or in spleen, but all progenitors, except cells sustaining MRACFU-NM, were reduced in hypoxic cultures.

401 citations


Journal ArticleDOI
TL;DR: The majority of TCC, derived under the same experimental conditions from the bronchial mucosa of two nonatopic patients with toluene diisocyanate‐induced asthma, were CD8+ and most of them produced interferon‐γ or interfer on‐γ and interleukin‐5, but not interleukain‐4, in response to nonspecific stimulation.
Abstract: Biopsy specimens were obtained from the bronchial or the nasal mucosa of three patients with grass pollen-induced bronchial asthma or rhinitis 48 h after positive bronchial or nasal provocation test with grass pollen extract. T cell clones (TCC), derived from these and control specimens, were then assessed for their phenotype, allergen-specificity, profile of cytokine secretion and ability to provide B cell help for IgE synthesis. Out of 50 and 61 CD4+ TCC derived from the bronchial mucosa of the two patient with atopic asthma 11 (22%) and 19 (31%), respectively, showed both proliferation and cytokine production in response to grass pollen allergens under major histocompatibility complex-restricted conditions. Of these 21 (70%) exhibited a clear-cut type 2 T helper (Th2) profile and induced IgE synthesis in autologous peripheral blood B cells in the presence of grass allergens. All the other 9 grass-specific clones showed a Th0 pattern of cytokine secretion, but only 1 provided moderate help for IgE synthesis. In contrast, the majority of TCC, derived under the same experimental conditions from the bronchial mucosa of two nonatopic patients with toluene diisocyanate-induced asthma, were CD8+ and most of them produced interferon-gamma or interferon-gamma and interleukin-5, but not interleukin-4, in response to nonspecific stimulation. Of 22 CD4+ TCC3 (14%) derived from the grass-stimulated mucosa of the patient with allergic rhinitis, but none of those derived from the unstimulated nostril of the same patient, exhibited proliferation and cytokine production in response to grass allergens. All had a clear-cut Th2 profile and provided help for IgE synthesis by autologous B cells. These data indicate that inhalation of the relevant allergen results in the activation of allergen-specific Th2 lymphocytes in the airway mucosa of patients with allergic respiratory disorders. These cells may play a central role in determining the nature of the inflammatory response in the airways of atopic patients.

341 citations


Journal ArticleDOI
TL;DR: Evidence is shown that Alzheimer's disease is a genetically heterogeneous disorder, and new approaches are delineated in the study of the etiological and pathogenetic mechanisms of Alzheimer’s disease.
Abstract: At present it is not clear whether Alzheimer’s disease is a single disease, a complex syndrome, or a heterogeneous ill-defined group of disorders. In the last few years significant progress has been made in identifying and describing its different manifestations, as well as the underlying biological mechanisms. Modern molecular biology techniques have provided new insights into possible etiological mechanisms. Linkage analysis and gene sequencing studies have produced evidence of a possible locus on chromosome 21 in a small group of families with early onset familial Alzheimer’s disease (FAD). It was shown that another small group of early onset FAD families develops the disease as a result of mutations in the gene coding for the s-amyloid precursor protein, and that in a larger subgroup of early onset families the disease appears to be caused by an unidentified gene on chromosome 14. Several other early onset FAD families are clearly not linked to any of these loci, suggesting that other abnormal genes, probably on different chromosomes, might be the cause of the disease in these families. Finally, it was recently shown that the e4 allele of apolipoprotein E (ApoE) gene, which has been mapped to chromosome 19, is associated with an increased risk of developing the disease in late onset FAD families and sporadic cases. These results not only evidence that Alzheimer’s disease is a genetically heterogeneous disorder, but also delineate new approaches in the study of the etiological and pathogenetic mechanisms of Alzheimer’s disease. (Aging Clin. Exp. Res. 5: 417–425, 1993).

278 citations


Journal ArticleDOI
01 Mar 1993-Blood
TL;DR: The effects of interferon-alpha (IFN-alpha) on clinical and serologic manifestations of mixed cryoglobulinemia (MC) were investigated by randomized, crossover-controlled trial in 26 patients.

262 citations


Journal ArticleDOI
TL;DR: Extensional and compressional regimes exist at the same time in adjacent parts of the Northern Apennines (Italy), and the former regime succeeded the latter at same place as the thrust mountain front moved eastward since Miocene times.

246 citations


Journal ArticleDOI
TL;DR: It is indicated that TGF-beta 1 is able to increase the synthesis of procollagen I, III, and FN in cultured human FSCs and can induce its own mRNA in the same cells.

Journal ArticleDOI
TL;DR: A significant correlation was found between PF problems and female gender, positive congruence angle, preoperative PF crepitation, rehabilitation difficulties, flexion loss greater than 10 degrees, extension loss more than 5 degrees, and variation in the height of the patella.
Abstract: A series of 226 anterior cruciate ligament (ACL) reconstructions were reviewed to determine the incidence of patellofemoral (PF) problems and the associated prognostic factors. Patients were divided into four groups according to the type of injury (acute or chronic) and operation (through an arthrotomy or arthroscopic assisted). The average follow-up period was 39 months. Overall there was a 5% incidence of PF crepitus with pain and/or swelling, and a further 20% of clear PF crepitus without pain. The change from open surgery and cast to arthroscopic surgery and early motion allowed a decrease of PF problems from 40% to 21% in acute injuries, but the difference was less marked in chronic knees. A deficit greater than 10% at the one-leg hop test was present in 75% of the knees with PF crepitus and pain. The height of the patella was increased in 5% and decreased in 17% of the knees. Patients with rehabilitation difficulties had the largest decrease in patella height, whereas a patella alta was more frequent after patellar tendon reconstruction. A significant correlation was found between PF problems and female gender, positive congruence angle, preoperative PF crepitation, rehabilitation difficulties, flexion loss greater than 10 degrees, extension loss greater than 5 degrees, and variation in the height of the patella. The importance of avoiding immobilization, rehabilitation difficulties, and permanent flexion or extension loss is emphasized.

Journal ArticleDOI
TL;DR: In this article, a three-dimensional code for rotating blade-row flow analysis was developed for the NASA rotor 67 transonic fan and a detailed study of the flow structure near peak efficiency and near stall was presented by means of pressure distribution and particle traces inside boundary layers.
Abstract: A three-dimensional code for rotating blade-row flow analysis was developed. The space discretization uses a cell-centered scheme with eigenvalues scaling for the artificial dissipation. The computational efficiency of a four-stage Runge-Kutta scheme is enhanced by using variable coefficients, implicit residual smoothing, and a full-multigrid method. An application is presented for the NASA rotor 67 transonic fan. Due to the blade stagger and twist, a zonal, non-periodic H-type grid is used to minimize the mesh skewness. The calculation is validated by comparing it with experiments in the range from the maximum flow rate to a near-stall condition. A detailed study of the flow structure near peak efficiency and near stall is presented by means of pressure distribution and particle traces inside boundary layers.

Journal ArticleDOI
TL;DR: MCP-1 secreted by FSC is stimulated by proinflammatory cytokines and that M CP-1 gene expression is upregulated in chronic inflammatory liver disease, indicating that MCP- 1 released by F SC may participate in the recruitment and activation of monocytes at sites of liver injury.
Abstract: Monocytes infiltrate the portal space during chronic liver inflammation. Monocyte chemotactic protein-1 (MCP-1) is a cytokine that induces monocyte chemotaxis and activation. We investigated if human liver fat-storing cells (FSC) secrete MCP-1, and the mechanisms that regulate MCP-1 production. Unstimulated FSC secrete MCP-1 as measured by radioimmunoassay as well as a chemotactic assay and express mRNA that encodes for this cytokine. A two- to threefold increase in MCP-1 secretion was observed when FSC were treated with either interleukin-1 alpha (IL-1 alpha) or interferon-gamma (IFN-gamma). Tumor necrosis factor-alpha (TNF alpha) also increased MCP-1 secretion, although to a lesser extent (1.6-fold). Northern blot analysis showed that IL-1 alpha and IFN-gamma strongly increase the levels of mRNA that encodes for MCP-1, whereas TNF alpha appears to be a weaker stimulus. Analysis of FSC-conditioned medium by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting revealed three bands of MCP-1 that most likely represent isoforms of different apparent molecular weights. Pretreatment of FSC with H-7, a protein kinase C inhibitor, blocked cytokine-induced increase in both MCP-1 gene expression and secretion. To determine the potential role of MCP-1 in vivo, we also analyzed normal and pathologic human liver tissue. Northern blot analysis showed that MCP-1 mRNA expression is more abundant in liver tissue obtained from patients with chronic active hepatitis compared with normal liver tissue. These studies indicate that MCP-1 secreted by FSC is stimulated by proinflammatory cytokines and that MCP-1 gene expression is upregulated in chronic inflammatory liver disease. MCP-1 released by FSC may participate in the recruitment and activation of monocytes at sites of liver injury.

Journal ArticleDOI
TL;DR: In this paper, an effective action approach to the resummation of all semiclassical contributions to the scattering phase arising in high-energy gravitational collisions is presented. But it is not shown that the superstring amplitude result is reproduced at first order in the expansion parameter R 2 / b 2, where R, b are the gravitational radius and the impact parameter, respectively.

Journal ArticleDOI
TL;DR: It is concluded that restrictive trade policies in industrialised countries have most likely added to migration pressures and the relationship between development levels, as measured by GDP per capita, and the propensity to migrate follows an inverse-U pattern.

Journal ArticleDOI
TL;DR: The efforts expended in chemical and biochemical modifications of 16-membered macrolides have been less successful, with only a few new molecules, such as rokitamycin and miocamycin, showing improved bioavailability and activity against some resistant micro-organisms.
Abstract: After the discovery of erythromycin and other natural compounds, including oleandomycin, spiramycin, josamycin and midecamycin, much research has been devoted to synthesizing derivatives or analogues with improved chemical, biological and pharmacokinetic properties. These new macrolides are semisynthetic molecules that differ from the original compounds in their substitution pattern of the lactone ring system. The chemical structure of macrolides is characterized by a large lactone ring containing from 12 to 16 atoms to which are attached, via glycosidic bonds, one or more sugars. The lactone ring is substituted by hydroxyl or alkyl groups, one ketone at C7 in 12-membered macrolides and at C9 in 14-membered macrolides, and one aldehyde group in 16-membered macrolides. The only compound with a 15-membered ring contains a tertiary amino group. Although the 12-membered macrolides have never become important in clinical practice, in recent years numerous new 14-membered macrolide derivatives of erythromycin A have shown improved pharmacokinetics due to chemical modifications of a hydroxyl group at C6, a proton at C8, or a ketone at C9. Derivatives, such as dirithromycin, roxithromycin, clarithromycin and flurithromycin, have all been synthesized with the aim of inhibiting their decomposition under acidic conditions to inactive anhydrohemiketal derivatives. A new 15-membered macrolide, azithromycin, with a methylated nitrogen inserted into the lactone ring shows good activity against Gram-negative bacteria. The efforts expended in chemical and biochemical modifications of 16-membered macrolides have been less successful, with only a few new molecules, such as rokitamycin and miocamycin, showing improved bioavailability and activity against some resistant micro-organisms.(ABSTRACT TRUNCATED AT 250 WORDS)


Journal ArticleDOI
TL;DR: This study provides evidence that cytolytic T cells with Th1 profile of cytokine production predominate in RO infiltrates of GO, a pattern quite similar to those previously described in thyroid infiltrate of Hashimoto's thyroiditis or Graves' disease.
Abstract: Lymphocytic infiltration of muscular and connective tissues of the retroorbital (RO) space is a histological hallmark of Graves' ophthalmopathy (GO). We have characterized some phenotypical and functional features of T cells derived from RO infiltrates of four GO patients who were submitted to orbital decompression. Fragments of RO tissue were cultured for 7 days in IL-2-conditioned medium in order to generate T cell lines of in vivo activated T cells. Phenotypical analysis of freshly isolated peripheral blood (PB) lymphocytes both from patients and four healthy controls showed a predominance of CD4+ T cells (CD4/CD8 ratios 1.9:2.5), whereas RO-derived T cell lines displayed almost equal proportions of CD4+ and CD8+ cells (CD4/CD8 ratios 0.9:1.2). RO T cell lines and PB T cells from patients and controls were then cloned using a high-efficiency cloning procedure. The phenotypical and functional features of 153 T cell clones (TCC) derived from RO infiltrates were examined and compared with those of 166 and...

Journal ArticleDOI
TL;DR: Data suggest sensitization in utero of T cells due to inhalation of these allergens by the mother during pregnancy.
Abstract: Umbelical cord blood lymphocytes showed consistent proliferation in response to Dermatophagoides group I ( Der p I) and occasionally even to Lolium group I ( Lol p

Journal ArticleDOI
TL;DR: Physicians should be alerted to the possibility of unusual toxicity that could also emerge in the future from the new and recently developed macrolide antibacterials, coinciding with their expanded clinical use worldwide.
Abstract: The renewed interest in macrolide antibacterials with expanded indications for clinical use, as well as their markedly increased usage, justifies the continuous search for new compounds designed to offer the patient not only enhanced bioavailability but also a reduced incidence of adverse effects. Macrolides are an old and well established class of antimicrobial agents that account for 10 to 15% of the worldwide oral antibiotic market. Macrolides are considered to be one of the safest anti-infective groups in clinical use, with severe adverse reactions being rare. Newer products with improved features have recently been discovered and developed, maintaining or significantly expanding the role of macrolides in the management of infection. This review deals with the tolerability of the clinically available macrolide antibacterials. With the exception of drug interactions, adverse effects have been analysed during the last 40 years in many thousands of adult and paediatric patients. Recently developed derivatives have been compared with the older compounds, and the expected and well assessed adverse effects have been set apart from those which are unusual, very rare or questionable. Gastrointestinal reactions represent the most frequent disturbance, occurring in 15 to 20% of patients on erythromycins and in 5% or fewer patients treated with some recently developed macrolide derivatives that seldom or never induce endogenous release of motilin, such as roxithromycin, clarithromycin, dirithromycin, azithromycin and rikamycin (rokitamycin). Except for troleandomycin and some erythromycins administered at high dose and for long periods of time, the hepatotoxic potential of macrolides, which rarely or never form nitrosoalkanes, is low for josamycin, midecamycin, miocamycin, flurithromycin, clarithromycin and roxithromycin; it is negligible or absent for spiramycin, rikamycin, dirithromycin and azithromycin. Transient deafness and allergic reactions to macrolide antibacterials are highly unusual and have definitely been shown to be more common following treatment with the erythromycins than with the recently developed 14-, 15- and 16-membered macrolides. There have been case reports in the literature of 51 patients during the last 30 years who experienced uncommon or dubious adverse effects after treatment with older compounds and in which there appears to be strong evidence of a causal relationship with the drug. Only 3 cases had an unfavourable outcome, and these were patients administered erythromycin lactobionate intravenously too rapidly or at high dose. Targets of these occasional reactions are generally the heart, liver and central nervous system. Other unusual organ pathologies are related to immunomediated disorders more than to primary parenchymal toxicity, or to the rarely serious consequences of macrolide-induced alterations in intestinal microflora.(ABSTRACT TRUNCATED AT 400 WORDS)

Journal ArticleDOI
TL;DR: In this article, a new way to study the dynamics of explosive behavior at different vents of Stromboli volcano is proposed, based on computer processing of images taken by an infrared film camera, at a rate of 4 pictures per second.

Journal ArticleDOI
TL;DR: Electrical signals elicited by integrin interaction with ECM components and their role in neurite outgrowth were studied in two clones isolated from 41A3 murine neuroblastoma cell line, revealing a similar implication of integrins in the adhesion of these clones to the ECM proteins.
Abstract: Electrical signals elicited by integrin interaction with ECM components and their role in neurite outgrowth were studied in two clones (N1 and N7) isolated from 41A3 murine neuroblastoma cell line. Although the two clones similarly adhered to fibronectin (FN) and vitronectin (VN), this adhesion induced neurite outgrowth in N1 but not in N7 cells. Patch clamp recordings in whole cell configuration showed that, upon adhesion to FN or VN but not to platelet factor 4 (PF4), N1 cells undergo a marked (approximately equal to 20 mV) hyperpolarization of the resting potential (Vrest) that occurred within the first 20 min after cell contact with ECM, and persisted for approximately 1 h before reverting to the time zero values. This hyperpolarization was totally absent in N7 cells. A detailed analysis of the molecular mechanisms involved in N1 and N7 cell adhesion to ECM substrata was performed by using antibodies raised against the FN receptor and synthetic peptides variously competing with the FN or VN binding to integrin receptor (GRGDSP and GRGESP). Antibodies, as well as GRGDSP, abolished adhesion of N1 and N7 clones to FN and VN, revealing a similar implication of integrins in the adhesion of these clones to the ECM proteins. However, these anti-adhesive treatments, while ineffective on Vrest of N7 cells, abolished in N1 cells the FN- or VN-induced hyperpolarization and neurite outgrowth, that appeared therefore strictly associated and integrin-mediated phenomena. The nature of this association was deepened through a comparative analysis of the integrin profiles and the ion channels of N1 and N7 cells. The integrin immunoprecipitation profile resulted very similarly in the two clones, with only minor differences concerning the alpha V containing complexes. Both clones possessed Ca2+ and K+ delayed rectifier (KDR) channels, while only N1 cells were endowed with inward rectifier K+ (KIR) channels. The latter governed the Vrest, and, unlike KDR channels, were blocked by Ba2+ and Cs+. By moving patched cells in contact with FN-coated beads, it was shown that KIR channel activation was responsible for the FN-mediated hyperpolarization of Vrest. Treatment with Pertuxis toxin (PTX) abolished this hyperpolarization and neurite outgrowth, indicating that a G protein is interposed between integrins and KIR channels and that the activation of these channels is required for neuritogenesis. In fact, the block of KIR channels by Cs+ abolished both hyperpolarization and neurite outgrowth, provided that the cation was supplied during the first two hours after N1 cell contact with FN.(ABSTRACT TRUNCATED AT 400 WORDS)

Journal ArticleDOI
03 Jun 1993-Nature
TL;DR: It is shown that HIV-infected T-cell clones do not express the CD40 ligand (CD40L), a molecule critical for non-cognate B-cell activation, but a small proportion of them do express membrane tumour-necrosis factor (TNF)-α, which seems to be involved in the polyclonal B- cell activation induced by HIV- infected T cells.
Abstract: Infection of CD4+ T cells by human immune deficiency virus-1 (HIV-1) causes severe dysfunction of cellular immunity, but paradoxically results in intense polyclonal activation of B cells, possibly accounting for both hypergammaglobulinaemia and frequent development of B-cell malignancies seen in HIV-infected patients. We have reported that human CD4+ T-cell clones infected with HIV in vitro markedly stimulate immunoglobulin synthesis by B cells through a non-cognate, contact-dependent mechanism. We show here that HIV-infected T-cell clones do not express the CD40 ligand (CD40L), a molecule critical for non-cognate B-cell activation, but a small proportion of them do express membrane tumour-necrosis factor (TNF)-alpha. The ability of HIV-infected T-cell clones to induce polyclonal B-cell activation appears to be restricted to TNF-alpha-positive T blasts and is inhibited by antibodies against both TNF-alpha and TNF-alpha receptor. Freshly isolated CD4+ T cells from HIV-infected individuals express TNF-alpha on the cell membrane and induce TNF-alpha-mediated immunoglobulin production by B cells. Thus, membrane TNF-alpha seems to be involved in the polyclonal B-cell activation induced by HIV-infected T cells.

Journal ArticleDOI
TL;DR: Although the changes seen in the inferior frontal cortex and occipital cortex may be related to anxiety experienced by the patients during the study, the pattern of hippocampal hypoperfusion appears to be characteristic of panic disorder.

Journal ArticleDOI
TL;DR: Viscosity measurements performed on Spirulina cultures having different biomass concentrations showed non‐Newtonian behavior displaying decreasing viscosity with an increasing shear rate, which corresponded to a net photosynthetic efficiency of 6.6% (based on visible irradiance).
Abstract: A photobioreactor in the form of a 245-m-long loop made of plexiglass tubes having an inner diameter of 2.6 cm was designed and constructed for outdoor culture of Spirulina. The loop was arranged in two planes, with 15 8-m-long tubes in each plane. In the upper plane, the tubes were placed in the vacant space between the ones of the lower plane. The culture recycle was performed either with two airlifts, one per plane, or with two peristaltic pumps. The power required for water recycle in the tubular photobioreactor, with a Reynolds number of 4000, was 3.93 x 10(-2) W m(-2). The photobioreactor contained 145 L of culture and covered an overall area of 7.8 m(2). The photobioreactor operation was computer controlled. Viscosity measurements performed on Spirulina cultures having different biomass concentrations showed non-Newtonian behavior displaying decreasing viscosity with an increasing shear rate. The performance of the two-plane photobioreactor was tested under the climatic conditions of central Italy (latitude 43.8 degrees N, longitude 11.3 degrees E). A biomass concentration of 3.5 g L(-1) was found to be adequate for outdoor culture of Spirulina. With a biomass concentration of 6.3 g L(-1), the biomass output rate significantly decreased. The net biomass output rate reached a mean value of 27.8 g m(-2) d(-1) in July; this corresponded to a net photosynthetic efficiency of 6.6% (based on visible irradiance).

Journal ArticleDOI
TL;DR: In this article, the geotectonic evolution of the Thessaly region (central-northern Greece) has been examined, using a quantitative and qualitative structural analysis; stratigraphie, sedimentological, morphotectology and seismological data.

Journal ArticleDOI
D. Buskulic1, I Debonis1, D. Decamp1, Philippe Ghez1  +396 moreInstitutions (24)
TL;DR: In this paper, a measurement of the partial width ratio using a method which tags the decays through the lifetimes of the produced heavy hadrons is presented, which relies on the tracking precision afforded by a double-sided silicon vertex detector.

Journal ArticleDOI
TL;DR: In this paper, the relationship between high-energy factorization and the factorization theorem of mass singularities is fully established by performing a complete resummed calculation in dimensional regularization, which is achieved by deriving and solving a new evolution equation for the gluon-gluon forward scattering amplitude at high energy in n space-time dimensions.

01 Aug 1993
TL;DR: Taking into account that heart failure is characterized by left ventricular dilation, reduced cardiac contractility, and increase of wall stress and peripheral vascular resistance, GH may be beneficial for treatment of heart failure.
Abstract: To investigate cardiac effects of excess and deficiency of growth hormone (GH) 20 acromegalic subjects and 11 adult patients with GH deficiency were studied by means of a non invasive method, the Doppler echocardiography. The results obtained in the group of patients were compared with those of 2 groups of 20 and 12 normal subjects, respectively, age and sex matched. The age of the acromegalic patients ranged from 20 to 62 years. Nineteen patients were considered to have active acromegaly at the time of the study. Mean duration of disease since treatment was 12 +/- 5 years (range 5 to 24 years). The age of GH deficient adults ranged from 21 to 33 years. All these patients have been treated with extractive GH over 9 years and the therapy withdrawal was performed at least 3 years before entering the study. In the acromegalic patient group, a subgroup including 9 patients with mild to moderate hypertension was considered. All subjects gave informed consent and the study protocol was approved by the Ethical Committee of the Medical School of Naples. Right ventricular free wall thickness resulted significantly increased in acromegalic patients (8 +/- 2 versus 4 +/- 1 mm; p < 0.001). Left ventricular mass index was augmented both in the whole group and in the subgroup of normotensive acromegalics as compared with normals (134 +/- 33 and 115 +/- 20 versus 80 +/- 18 g.m-2; p < 0.01). Ejection phase indices were normal in patient group, while impaired left and right ventricular diastolic filling was found.(ABSTRACT TRUNCATED AT 250 WORDS)