Neural coding of spatial phase in V1 of the macaque monkey

We examine the responses of single neurons and pairs of neurons, simultaneously recorded with a single tetrode in the primary visual cortex of the anesthetized macaque monkey, to transient presentations of stationary gratings of varying spatial phase. Such simultaneously recorded neurons tended to have similar tuning to the phase of the grating. To determine the response features that reliably discriminate these stimuli, we use the metric-space approach extended to pairs of neurons. We find that paying attention to the times of individual spikes, at a resolution of approximately 30 ms, and keeping track of which neuron fires which spike rather than just the summed local activity contribute substantially to phase coding. The contribution is both quantitative (increasing the fidelity of phase coding) and qualitative (enabling a 2-dimensional "response space" that corresponds to the spatial phase cycle). We use a novel approach, the extraction of "temporal profiles" from the metric space analysis, to interpret and compare temporal coding across neurons. Temporal profiles were remarkably consistent across a large subset of neurons. This consistency indicates that simple mechanisms (e.g., comparing the size of the transient and sustained components of the response) allow the temporal contribution to phase coding to be decoded.     

Effect of surface treatment on the shear bond strength of three resin cements to a machinable feldspatic ceramic

The aim of this study was to evaluate the shear bond strength of three resin cements to Vita Mark II ceramics under different pretreatments of the ceramic surface and to examine whether simplified pretreatment procedures would result in satisfying results compared to the state of the art. RelyX Unicem (RXU), Calibra (CAL), and Variolink II (VAR) were used as resin cements and bonded to machine milled feldspatic disks, pretreated in five different ways. (1) no pretreatment of the ceramic surface; (2) surface etched with hydrofluoric acid (HF); (3) ceramic surface silanized; (4) ceramic surface etched (HF) and silanized, (5) ceramic surface etched (HF), silanized, and covered with Heliobond. The shear bond strengths were measured initially, after 5000 and 10,000 thermocycles (TC). After 10,000 TC for CAL only procedure 5 resulted in a reliable adhesion median value of 10.7 MPa. VAR showed median values of 24.6, 17.2, and 18.1 MPa for pretreatments 5, 3, and 4, respectively. RXU performed 25.9, 22.0, and 11.0 MPa for procedures 5, 4, and 3, respectively. For procedure 2, RXU revealed the significantly highest value with 15.4 MPa (U-test, p = 0.05). Only RXU-luted specimens of procedure 1 survived the 10,000 thermocycles. The results revealed that a simplification of the ceramic pretreatment for VAR and RXU might be possible.     

Selective recognition of DNA antigenic determinants by murine monoclonal anti-DNA antibodies.

To assess the immune recognition of DNA in systemic lupus erythematosus, the antigenic specificity of monoclonal anti-DNA antibodies from autoimmune MRL-lpr/lpr mice was investigated Determinant specificity was assessed by ELISA in terms of binding to a panel of ssDNA antigens including calf thymus, human placenta, Escherichia coli, Clostridium perfringens, Micrococcus lysodeikticus, salmon testes, chicken blood and murine DNA. Among the monoclonal antibodies, a variety of binding patterns was observed, although for all antibodies tested murine DNA was among the most reactive antigens. Binding to other DNAs varied markedly, with some antibodies showing only low reactivity to certain antigens in the test panel. Similar results were obtained with sera of individual MRL-lpr/lpr mice. These results suggest that anti-DNA antibodies bind specific antigenic determinants variably expressed by DNAs of various species. Furthermore, the preferential binding to mouse DNA by some MRL-lpr/lpr antibodies may suggest a role of self-DNA in the in vivo selection of anti-DNA antibodies for expression.     

Effect of cytofectins on the immune response of murine macrophages to mammalian DNA

DNA, depending on base sequence, can induce a wide range of immune responses. While bacterial DNA is stimulatory, mammalian DNA is inactive alone and can, moreover, inhibit the response to bacterial DNA. To determine whether the mode of cell entry affects the immune properties of mammalian DNA, we have investigated the effects of the cytofectin agents Fugene 6 (Roche Diagnostics Corp., Indianapolis, IN), Lipofectin and Lipofectamine (Life Technologies, Grand Island, NY) on the responses of murine macrophages to DNA from calf thymus and human placenta. Whereas calf thymus and human placenta DNA alone failed to stimulate J774 or RAW264.7 cell lines or bone marrow-derived macrophages, these DNAs in complexes with cytofectin agents stimulated macrophages to produce nitric oxide but not interleukin 12. Both single-stranded and double-stranded DNAs were active in the presence of cytofectins. Macrophage activation by the DNA-cytofectin complexes was reduced by chloroquine, suggesting a role of endosomal acidification in activation. As shown by flow cytometry and confocal microscopy, the cytofectins caused an increase in the uptake of DNA into cells. Our findings indicate that macrophages vary in their response to DNA depending on uptake pathway, suggesting that activation by DNA reflects not only sequence but also context or intracellular location.     

Diagnostic value of mucin-histochemical reaction in biopsy specimens of the large bowel

The present study was carried out to determine the value of mucin-histochemical reactions in normal and pathologically altered colorectal mucosa. Normal large bowel mucosa shows a regionally different pattern of mucin composition of the goblet cell. In adenomas, remarkable variations of mucin pattern can be observed. Well-differentiated adenocarcinomas contain only sparse amounts of sialomucin or neutral mucins but no sulfomucins. In inflamed large bowel mucosa, the content of sulfomucins decreases in dependence on the degree of inflammation. The changes of mucin composition in the goblet cells are of unspecific reactive nature because they can be observed in the same manner in neoplastic and inflamed mucosa. With the employed mucin-histochemical methods no essential informations can be obtained in addition to pathohistological diagnosis.     

Matrix metalloproteinases (MMP), EMMPRIN (extracellular matrix metalloproteinase inducer) and mitogen-activated protein kinases (MAPK): Co-expression in metastatic serous ovarian carcinoma

Activation or suppression of intracellular signaling via the mitogen-activated protein kinase (MAPK) family has been linked to expression of matrix metalloproteinases (MMP) in experimental models, but this association has not been demonstrated in clinical material. The objective of this study was to investigate the possible association between expression and activity of MMP, expression of the MMP inducer EMMPRIN, and the expression (level) and phosphorylation status (activity) of the extracellular-regulated kinase (ERK), c-Jun amino-terminal kinase (JNK) and high osmolarity glycerol response kinase (p38) in effusions from patients diagnosed with serous ovarian carcinoma. MAPK level and activity were studied in 55 effusions using immunoblotting. MMP-1, MMP-2, MMP-9 and EMMPRIN expression was studied using immunocytochemistry (ICC) and mRNA in situ hybridization (ISH). The gelatinolytic activity of MMP-2 and MMP-9 was measured by zymography. ERK and phospho-ERK (p-ERK) were detected in 54/55 (98%) and 50/55 (91%) specimens, respectively. JNK and p-JNK were detected in 53/55 (96%) and 38/55 (69%) specimens, respectively. p38 was expressed in 54/55 (98%) specimens, and its phosphorylated form was found in 51/55 (92%). MMP-2 mRNA expression (P=0.048), protein expression (P=0.046) and gelatinolytic activity (P=0.039) correlated with ERK phosphorylative activity. MMP-2 activity also correlated with p38 activity (P=0.017). MMP-9 protein expression correlated with phosphorylation of p38 (P=0.046), but enzyme activity showed inverse relationship with both p-ERK (P=0.05) and p-p38 (P=0.033) expression. EMMPRIN expression correlated with MMP-1 (P<0.001), MMP-2 (P=0.042) and MMP-9 (P=0.029) expression, as well as with ERK activity (P=0.001). Our results present the first evidence of a possible link between MAPK signaling and MMP expression and activity in vivo. These data may expand our understanding regarding the mechanisms by which MMP synthesis is regulated in effusions and possibly affect treatment strategies for this form of malignancy. This revised version was published online in July 2006 with corrections to the Cover Date.     

Inhibition of murine macrophage IL-12 production by natural and synthetic DNA

DNA is a complex macromolecule whose immunological properties vary with sequence and structure. To determine whether DNA can inhibit immune responses, the effects of mammalian DNA and synthetic phosphodiester (Po) and phosphorothioate (Ps) oligonucleotides (ODNs) on IL-12 production were tested using murine macrophages. With bacterial DNA as a stimulant, calf thymus DNA and human placenta DNA blocked IL-12 production by splenic and bone marrow macrophages. A (dG)(30) Po ODN and all single-base Ps 30 mer ODNs were also effective inhibitors. The Ps ODNs also blocked IL-12 production induced by lipopolysaccharide (LPS) and a stimulatory Ps ODN. With the J774 cell line, single-base Ps ODNs inhibited IL-12 production induced by bacterial DNA, LPS, and a stimulatory Ps ODN. Together, these results indicate that DNA has inhibitory properties, suggesting that mammalian DNA could limit immune activation during inflammation and counteract the effects of bacterial DNA.