Laterality of manual function in foraging and positional behavior in wild indri (Indri indri)

This research is based on the idea that some prosimian species are good models in which to test certain postulates of the "postural origins" theory proposed by MacNeilage and colleagues [Behavioral and Brain Sciences 10:247-303, 1987] to explain the evolution of hand preference within the order Primates. We investigated manual laterality in 16 wild indris (eight males and eight females, living in four social groups) in their habitat, the Madagascan tropical rain forest. Data were collected on two spontaneous behaviors: "branch-reach," an action that occurs during foraging, and "higher support," a posture typical of clingers and leapers. A total of seven subjects were significantly lateralized for branch-reach (two showed a right preference, and five showed a left preference). Four subjects were significantly lateralized for higher support, and all of them showed a right-hand preference. Most of the indris we studied showed no preference. Our research suggests that indri are at "level 1 of laterality" in the classification framework proposed by McGrew and Marchant [Yearbook of Physical Anthropology 40:201-232, 1997]. The data presented here are not discordant with the "postural origins" theory, as lateralized subjects are often in the direction predicted by MacNeilage and colleagues [Behavioral and Brain Sciences 10:247-303, 1987], but they are the minority.     

New pharmacokinetic and pharmacodynamic tools for interferon-alpha (IFN-α) treatment of human cancer

Interferon (IFN-) has been widely used in the treatment of human solid and haematologic malignancies. Although the antitumour activity of IFN- is well recognised at present, no major advances have been achieved in the last few years. Recent findings have provided new information on the molecular mechanisms of the antitumour activity of the cytokine. In fact, IFN- appears to block cell proliferation, at least in part, through the induction of apoptotic effects. This cytokine can also regulate the progression of tumour cells through the different phases of the cell cycle inducing an increase of the expression of the cyclin-dependent kinase inhibitors p21 and p27. However, it must be considered that IFN- is a physiologic molecule with ubiquitously expressed receptors that is likely to activate survival mechanisms in the cell. We have recently identified an epidermal growth factor (EGF) Ras-dependent protective response to the apoptosis induced by IFN- in epidermoid cancer cells. The identification of tissue- and/or tumour-specific survival pathways and their selective targeting might provide a new approach to improve the efficacy of IFN-–based treatment of human cancer. Moreover, new pegylated species of IFN- are now available with a more favourable pharmacokinetic profile. We will review these achievements, and we will specifically address the topic of IFN-–based molecularly targeted combinatory antitumour approaches.     

Is myosin light-chain phosphorylation a regulatory signal for the osmotic activation of the Na+-K+-2Cl- cotransporter?

Myosin light-chain (MLC) kinase (MLCK)-dependent increase in MLC phosphorylation has been proposed to be a key mediator of the hyperosmotic activation of the Na⁺-K⁺-2Cl^– cotransporter (NKCC). To address this hypothesis and to assess whether MLC phosphorylation plays a signaling or permissive role in NKCC regulation, we used pharmacological and genetic means to manipulate MLCK, MLC phosphorylation, or myosin ATPase activity and followed the impact of these alterations on the hypertonic stimulation of NKCC in porcine kidney tubular LLC-PK1 epithelial cells. We found that the MLCK inhibitor ML-7 suppressed NKCC activity independently of MLC phosphorylation. Notably, ML-7 reduced both basal and hypertonically stimulated NKCC activity without influencing MLC phosphorylation under these conditions, and it inhibited NKCC activation by Cl^– depletion, a treatment that did not increase MLC phosphorylation. Furthermore, prevention of the osmotically induced increase in MLC phosphorylation by viral induction of cells with a nonphosphorylatable, dominant negative MLC mutant (AA-MLC) did not affect the hypertonic activation of NKCC. Conversely, a constitutively active MLC mutant (DD-MLC) that mimics the diphosphorylated form neither stimulated isotonic nor potentiated hypertonic NKCC activity. Furthermore, a depolarization-induced increase in endogenous MLC phosphorylation failed to activate NKCC. However, complete abolition of basal MLC phosphorylation by K252a or the inhibition of myosin ATPase by blebbistatin significantly reduced the osmotic stimulation of NKCC without suppressing its basal or Cl^– depletion-triggered activity. These results indicate that an increase in MLC phosphorylation is neither a sufficient nor a necessary signal to stimulate NKCC in tubular cells. However, basal myosin activity plays a permissive role in the optimal osmotic responsiveness of NKCC. proline-alanine-rich STE20-related kinase     

Role of IL-6 and CD23 in the resistance to growth arrest and apoptosis in LCL41 B lymphoma cells

Interleukin-6 (IL-6) is a growth and survival factor in Epstein-Barr virus (EBV)-infected B lymphoma cells and IL-6 antagonists have been used in clinical practice for this pathology. We thus wanted to investigate the effect of the IL-6 receptor antagonist Sant7 on proliferative and anti-apoptotic signals in the IL-6-secreting LCL41 B lymphoid cells, taken from a patient with EBV-induced lymphoproliferative disorder. Results show efficient inhibition of constitutive Stat3 activation by Sant7. However, this inhibition is associated with marginal induction of apoptosis and with minor decrease of cell proliferation, contrary to the effect of the Jak kinase inhibitor AG490, which down-regulates both proliferation and Stat3 activation. Anti-apoptotic markers such as Bcl-xL or Mcl-1 are constitutively expressed in these cells, and their expression is not affected by Sant7 treatment. Inhibition of Stat3 activation is therefore not sufficient to prevent proliferation and to induce apoptosis in these cells. In addition, low cell density is a condition favouring inhibition of cell clustering and anti-proliferative Sant7 activity. A marked inhibition of cell cluster formation and proliferation is achieved by antibody treatment against the CD23 mature B cell surface marker expressed in LCL41 cells. These findings may thus contribute to the identification of possible resistance mechanisms to growth arrest in B cell lymphoproliferative conditions.     

Focused library design in GPCR projects on the example of 5-HT(2c) agonists: comparison of structure-based virtual screening with ligand-based search methods

The aim of this study was to investigate the usefulness of structure-based virtual screening (VS) for focused library design in G protein-coupled receptors (GPCR) projects on the example of 5-HT(2c) agonists. We compared the performance of structure-based VS against two different homology models using FRED for docking and ScreenScore, FlexX, and PMF for rescoring with the results of 12 ligand-based similarity searches using four different query compounds and three different similarity metrics (Daylight, FTree, Phacir). The result of the similarity search showed much variation, from an enrichment factor up to 3.2 to worse than random, whereas the structure-based VS gave a more stable result with a constant enrichment factor around 2. Additionally, actives retrieved by the structure-based approach were more diverse than the actives among the top scorers of the similarity searches. Based on these results, we suggest basing a focused library design for a GPCR project on a combination of a ligand-based similarity search and structure-based docking.     

Interactions between Mytilus haemocytes and different strains of Escherichia coli and Vibrio cholerae O1 El Tor: role of kinase-mediated signalling

Marine bivalves accumulate large amounts of bacteria from the environment (mainly Vibrionaceae and coliforms). Although persistence of different bacteria in bivalve tissues largely depends on their sensitivity to the bactericidal activity of circulating haemocytes and haemolymph soluble factors, the mechanisms involved in bacteria-host cell interactions in these invertebrates are largely unknown. In the mussel Mytilus, differences in interactions between haemocytes and different Escherichia coli and Vibrio cholerae strains [E. coli MG155, a wild-type strain carrying type 1 fimbriae, and its unfimbriated derivative, AAEC072 Deltafim; V. cholerae O1 El Tor biotype strain N16961, carrying the mannose-sensitive haemagglutinin (MSHA), and its MSHA mutant] lead to differences in bactericidal activity in the presence of serum. Here we show that different bacteria induced distinct patterns of phosphorylation of mitogen-activated protein kinases (MAPKs), in particular of the stress-activated MAPKs involved in the immune response. Differences in phosphorylation of PKC-like proteins were also observed. The results support the hypothesis that, like in mammalian host cells, different bacteria can modulate the signalling pathways of mussel haemocytes. The lower anti-bacterial activity towards the mutant E. coli strain and wild-type V. cholerae compared with wild E. coli may result from a reduced capacity of activating MAPKs. Moreover, the mutant V. cholerae strain that was the most resistant to the haemocyte bactericidal activity induced downregulation of cell signalling and showed the strongest effect on lysosomal membrane stability, evaluated as a marker of bivalve cell stress. These data suggest that certain bacteria could evade the bactericidal activity of mussel haemocytes through disruption of the host signalling pathways.     

Tissue arrays as fiducial markers for section alignment in 3-D reconstruction technology

Combination of conventional histology and the three-dimensional spatial view of tissue structures offers new prospects for understanding and diagnosing nature and development of human diseases. The essential technical problem related to three-dimensional reconstruction in histopathology is represented by the correct alignment of serial sections. During the past years several methods have been proposed but failed to become popular because of their limits in terms of time consume and restricted applicability. We aimed to overcome this problem by applying the technology of Tissue Array, thus by positioning adequate fiducial markers from specific "donor" blocks into the "recipient" paraffin block of interest. Digitized pictures of serially cut sections were aligned according to the tissue markers embedded by Tissue Array, and then processed with specific softwares for three-dimensional reconstruction. Thirteen models, including fetal hearts, breast and thyroid carcinomas, were elaborated. We found the procedure to be easy, fast and reproducible. Moreover, by selectively embedding the fiducial markers according to specific angles, the Tissue Arrays can be exploited in order to establish the distance between sections. This original methodology of incorporating Tissue Arrays into paraffin blocks as fiducial markers for three-dimensional reconstruction has a potential impact on histology for research purposes and diagnostic applications.