Functional expression and properties of the human skeletal muscle sodium channel

Full-length deoxyribonucleic acid, complementary (cDNA) constructs encoding the-subunit of the adult human skeletal muscle Na⁺ channel, hSkM1, were prepared. Functional expression was studied by electrophysiological recordings from cRNA-injectedXenopus oocytes and from transiently transfected tsA201 cells. The Na⁺ currents of hSkM1 had abnormally slow inactivation kinetics in oocytes, but relatively normal kinetics when expressed in the mammalian cell line. The inactivation kinetics of Na⁺ currents in oocytes, during a depolarization, were fitted by a weighted sum of two decaying exponentials. The time constant of the fast component was comparable to that of the single component observed in mammalian cells. The block of hSkM1 Na⁺ currents by the extracellular toxins tetrodotoxin (TTX) and -conotoxin (CTX) was measured. The IC₅₀ values were 25 nM (TTX) and 1.2 M (CTX) in oocytes. The potency of TTX is similar to that observed for the rat homolog rSkM1, but the potency of CTX is 22-fold lower in hSkM1, primarily due to a higher rate of toxin dissociation in hSkM1. Single-channel recordings were obtained from outside-out patches of oocytes expressing hSkM1. The single-channel conductance, 24.9 pS, is similar to that observed for rSkM1 expressed in oocytes.     

Télomères monofonctionnels du chlorure de vinyle, 3. Cinétique par catalyse rédox

A kinetic study of the redox telomerization of vinyl chloride with carbon tetrachloride was carried out. Transfer constants of PVC to the metallic ion (C_Feⁿ), initiation rate (k_i), and functionnality of the resulting telomers were measured. Instantaneous and cumulated polymerization degrees, (DP_n )_i and (DP_n )_cum were determined with the help of a theoretical study. These constants provide a rigorous control of the telomerization of vinyl chloride with RCCl₃, (R containing an alcohol or ester group).     

Expression of CD4 on peripheral blood granulocytes. a novel finding in a case of myelodysplastic syndrome in association with t(5;12)

Myelodysplastic syndromes (MDS) are associated with cell maturation defects that can manifest as abnormal surface antigen expression. We describe a patient with refractory anemia with excess blasts, who presented with infection and extensive dysplastic features in peripheral blood granulocytes. The granulocytes expressed CD11b, CD13, CD15, CD33, and CD43. The granulocytes also expressed CD4 antigen. Cytogenetic analysis showed a clonal t(5;12)(q33;p13). The patient improved on antibiotics with partial improvement in the dysplastic features. However, shortly after, the patient experienced paravertebral extramedullary blast transformation followed by a leukemia phase of acute monoblastic leukemia. The patient died a few days later. This is the first report describing anomalous expression of CD4 on granulocytes in MDS. Since the breakpoint on chromosome 12 is near the CD4 gene, which is mapped to 12p12, we hypothesize that dysregulation of the CD4 gene may have occurred resulting in its persistent expression on mature and maturing granulocytes.     

Favorably tipping the balance between cytopathic and regulatory T cells to create transplantation tolerance

Therapeutic application of broadly reactive anti-T cell antibodies can lead not only to potent immunosuppression but also to profound and long-lived T cell depletion. We reasoned that a strategy that almost exclusively targets activated cytopathic donor reactive T cells and spares immunoregulatory networks might prove to be an exceptionally potent and highly selective means of producing long-term engraftment and tolerance. Herein we show that the combined administration of rapamycin and agonist IL-2- and antagonist IL-15-related cytolytic fusion proteins provides for long-term engraftment/tolerance in exceptionally stringent allotransplant models by (1) limiting the early expansion of activated T cells, (2) preserving and even exaggerating their subsequent apoptotic clearance, and (3) further amplifying the depletion of these activated T cells by antibody-dependent mechanisms, while (4) preserving CD4+CD25+ T cell-dependent immunoregulatory networks.     

Detection of fish antigens aerosolized during fish processing using newly developed immunoassays

BACKGROUND: Aerosolization of fish proteins during seafood processing has been identified as a potential route for allergic sensitization and occupational asthma among workers involved in high-risk activities. The aim of this study was to develop immunological assays for the quantification of aerosolized fish antigens in a fish-processing factory. METHODS: Polyclonal antibodies to the main fish species processed in the factory (anchovy and pilchard) were generated in rabbits and compared by ELISA inhibition assay and immunoblotting. These antisera were utilized to develop ELISA assays for the detection of fish antigens. The ELISA inhibition assays were evaluated by analyzing environmental air samples collected from three areas in a fish-processing factory: pilchard canning, fish meal production and lobster processing. RESULTS: By immunoblotting, the rabbit polyclonal antibodies demonstrated IgG antibody binding patterns comparable with IgE antibodies of fish-sensitized patients, particularly in regard to the major fish allergens parvalbumins. The sensitivity of the fish-specific ELISA assays developed was 0.5 microg/ml. The ELISA inhibition assays were able to differentiate between the two different fish species of interest but did not recognize a crustacean species. Notable differences in exposure levels to canned pilchard and anchovy antigens were demonstrated in the three different working areas of the factory, with assays having a detection limit as low as 105 ng/m(3). CONCLUSION: These ELISA-based assays are sensitive and specific to quantify differential exposure levels to fish antigens produced during fish processing, making it possible to investigate exposure-disease response relationships among workers in this industry.     

Chromosome analyses of 16 cases of Wilms tumor: different pattern in unfavorable histology

Cytogenetic analyses of 16 cases of Wilms tumor with abnormal karyotypes were reviewed, 15 cases of unilateral tumor and 1 bilateral. Three tumors exhibited an unfavorable histology (i.e., anaplastic changes); the rest fell into the favorable histology group. Of the 17 tumors with abnormal clonal aberrations, 9 tumors were hyperdiploid (53%), 7 had pseudodiploid karyotypes (41%), and 1 was hypodiploid (6%). The most common numerical aberrations in descending order of frequency were gain of chromosomes 12, 8, and 6 and loss of chromosome 16. Structural rearrangements mostly involved chromosome 1, followed by chromosomes 7, 14, and 17. Clustering of breaks around 1p22 approximately p31-->pter resulting in partial loss of 1p was the most frequent structural aberration. Additionally, i(7q) was observed as a sole abnormality in two tumors and a 7p translocation in two other tumors. Two other recurrent abnormalities were a partial deletion of 14q, seen in three tumors, and complete loss of chromosome 14 in one tumor. All three Wilms tumors with unfavorable histology had abnormalities of 17p, resulting in TP53 gene deletion. These findings provide further support for the importance of gains of chromosomes 12, 8, and 6 and loss of 1p in the development of Wilms tumor. The results also support the association of unfavorable-histology Wilms tumors with TP53 deletion. The nonrandom losses of 16/16q, 7p, and 14q may point to the importance of genomic imbalance in the pathogenetic consequences and progression of Wilms tumor.     

Photodynamic therapy induced Fas-mediated apoptosis in human carcinoma cells

Photodynamic therapy (PDT) is a clinical approach that utilizes light-activated drugs for the treatment of a variety of pathologic conditions. Human poorly (CNE2) and moderately differentiated (TW0-1) human nasopharyngeal carcinoma (NPC) cells undergo rapid apoptosis when treated with PDT sensitized with Hypocrellin A (HA) and Hypocrellin B (HB). It has been shown that these compounds have a strong photodynamic effect on tumors and viruses. The initiating events of PDT sensitized HA and HB-induced apoptosis are poorly defined. In the current study, we sought to determine whether Fas/FasL upregulation and involvement of mitochondrial events are an early event in HA and HB-treated PDT induced apoptosis. Loss of mitochondrial transmembrane potential, release of cytochrome c, involvement of caspases-8 and -3 and the status caspase-3 specific substrate PARP, were evaluated in PDT treated tumor cells. Photoactivation of HA and HB enhanced both CD95/CD95L expression and induced CD95-signaling dependent cell death in all tumor cell lines studied. CD95/ CD95L expression appeared within 2 h following light activation and appeared to be a primary event in PDT induced apoptosis. Furthermore, these results indicate that release of mitochondrial cytochrome c into the cytoplasm is a secondary event following the activation of initiator caspase-8 preceding caspase-3 activation, cleavage of PARP and DNA fragmentation. Cytochrome c appeared in the cytosol within 2-3 h post PDT. Cleavage of PARP was observed at 3-4 h following PDT and caspase-3 specific inhibitor DEVD-CHO and broad-spectrum caspases inhibitor z-VAD-fmk blocked caspase-3 activation and PARP cleavage suggesting that caspase-3 plays an important role in HA and HB-induced apoptosis.     

The effects of inversion and eye displacements of familiar and unknown faces on early and late-stage ERPs.

OBJECTIVES: The objective of this study is to examine whether configural alterations of faces affect early or late processing stages as a function of their familiarity and their level of representation in memory. We then sought to verify whether the structural encoding stage is susceptible to top-down influences. METHODS: Electrophysiologic and behavioral studies were undertaken, during which unknown and familiar faces were presented upright or upside-down with or without feature alterations. The subjects were asked to determine whether the faces were familiar or not. RESULTS: N170 and N360 amplitudes were larger for familiar faces as well as altered ones. A higher degree of familiarity decreased reaction times (RTs) and N360 latencies, but increased N170 latencies, whereas face alterations increased RTs and latencies of both components examined. However, familiarity interacted with altered face configurations only for RTs and the N170. SIGNIFICANCE: In the perceptual stage, familiar faces seem to develop a more elaborate type of processing because of top-down influences linked to the robust nature of their representations in memory. The more elaborate type of processing for familiar faces has advantageous consequences for the following steps of information processing, by facilitating access to structural representations in memory (N360) as well as the final step reflected by RTs. The fact that configural alterations cause different effects for familiar as opposed to unfamiliar faces indicate that these stimuli are processed in a qualitatively different manner and solicit different representations in memory.