On the temporal relations between memory scanning and response preparation

Three experiments were conducted to investigate whether response processes can start before memory scanning has finished when both are required in the same task. In Experiment 1 the color of a stimulus letter determined which hand might respond, and the letter's memory set membership determined whether that response should be made or withheld. Electrophysiological data suggested that lateralized response preparation was not initiated until memory scanning finished. Experiment 2 replicated these results with a consistent stimulus-response mapping to make the scanning process easier. Experiment 3 tested for earlier response priming with a probe reaction time paradigm, and the results suggested that color information can be used to activate a response before memory scanning is finished. The results of Experiments 1-3 suggest that interference between memory scanning and response preparation precludes the concurrent operation of these processes.     

Calmodulin is essential for estrogen receptor interaction with its motif and activation of responsive promoter

Calmodulin (CaM) has been reported to have affinity for the estrogen receptor (ER). Observations reported here reveal a direct physical interaction between purified CaM and ER. This direct ER-CaM interaction may be an initial event preceding the assembly of ER plus auxiliary proteins into the active ER complex with its DNA motif, the estrogen response element. We demonstrate that CaM is an integral component of this complex by using a system reconstituted from purified ER and nuclear extract from ER-negative breast cancer cells and also with ER-depleted nuclear extract of an ER-positive breast cancer cell line. Although CaM is essential for formation of this complex, it is not sufficient, suggesting roles also of auxiliary proteins. CaM also is functionally required for activation of an ER-responsive promoter, in the 17beta-estradiol-ER pathway of hormone action and regulation of 17beta-estradiol-responsive gene expression that is associated with proliferation of mammary epithelial cells.     

Efficacy of arthroscopic lysis and lavage in patients with temporomandibular joint symptoms associated with generalized osteoarthritis or rheumatoid arthritis

PURPOSE: This study evaluated the efficacy of arthroscopic lysis and lavage in patients with temporomandibular joint (TMJ) symptoms and generalized osteoarthritis (GOA) or rheumatoid arthritis (RA). PATIENTS AND METHODS: Twenty-three GOA patients and 23 RA patients were evaluated after 1 year. RESULTS: Seventeen of 23 patients (74%) in the RA group improved after arthroscopic lysis and lavages compared with 10 of 23 (43%) of the GOA patients. Lateral joint tenderness, crepitation, maximal opening, and maximal protrusion showed most improvement in the RA group. CONCLUSIONS: On the basis of this short-term follow-up study, arthroscopic lysis and lavage seem to provide an effective treatment for TMJ pain and dysfunction in RA patients but not in GOA patients.     

Detraining from total body exercise ergometry in individuals with spinal cord injury

Fibroblast-mediated cytokine gene therapy has proven to be a promising strategy for restoring hematopoiesis following repeated chemotherapy. Interleukin 3 (IL-3) and interleukin 6 (IL-6) can synergistically promote the recovery of hematopoiesis following chemotherapy. In this investigation, combined use of fibroblast-mediated IL-3 and IL-6 gene therapy was tested for hematopoietic effects on mice with or without 5-fluorouracil administration. The results demonstrated that combined therapy with IL-3 gene-modified NIH3T3 cell (NIH3T3-IL-3) and IL-6 gene-modified fibroblast NIH3T3 cell (NIH3T3-IL-6) implantation achieves obvious stimulation of hematopoiesis in normal mice and accelerates recovery of hematopoiesis. In normal mice the quantities of platelets, neutrophils, and total white blood cells in peripheral blood increased significantly after the combined implantation of NIH3T3-IL-3 and NIH3T3-IL-6 cells. The numbers of colony-forming unit (CFU) granulocyte/macrophage (CFU-GM) and CFU megakaryocyte (CFU-MK) formed by stem cells in bone marrow was significantly higher after the combined implantation of NIH3T3-IL-3 and NIH3T3-IL-6 cells than after the implantation of NIH3T3-IL-3 alone, NIH3T3-IL-6 alone, or neomycin gene-modified NIH3T3 cells. In hematopoiesis-depressed mice induced by preinjection with 5-fluorouracil at the dose of 150 mg/kg before cell implantation, the platelets, neutrophils, and white blood cells showed accelerated recovery, and the numbers of CFU-GM and CFU-MK formed by bone marrow cells were also markedly higher after the combined implantation of NIH3T3-IL-3 and NIH3T3-IL-6 cells than in control groups. Our data show that combined use of fibroblast-mediated IL-3 and IL-6 gene therapy may be of clinical relevance for the recovery of hematopoietic depression for patients after chemotherapy.     

Oral administration of rapamycin and cyclosporine differentially alter intestinal function in rabbits

The immunosuppressive drugs rapamycin (Rap) and cyclosporine A (CsA) are used clinically to modify or abolish immune-mediated functions. This study examined the effect of orally administered regimens of Rap, CsA, and a combination of Rap/CsA on intestinal function in male New Zealand white rabbits. Animals received oral doses of CsA (15 mg/kg/body weight/day), low-dose (LD) and high-dose (HD) Rap (0.25 or 1 mg/kg/body wt/day, respectively), or Rap/CsA (0.25 and 5 mg/kg/body wt/day, or 0.5 and 5 mg/kg/body wt/day, respectively) for 20 days. We measured in vitro uptake of nutrients and permeability, and morphometric measurements in the jejunum and ileum were made. Animals receiving HD-Rap or HD-Rap/CsA had decreased food intake, body weight, and intestinal weight, when compared with LD-Rap, LD-Rap/CsA, CsA, or controls. The maximal transport rate (Vmax) for the active jejunal uptake of D-glucose was increased in HD-Rap and CsA, but not in the HD-Rap/CsA-treated animals. The jejunal Vmax of D-glucose in the LD-Rap- or -Rap/CsA-treated animals was no different from controls. In the HD-Rap- and HD-Rap/ CsA-treated animals, jejunal rates of uptake of stearic, linoleic, and linolenic acids were reduced when compared with controls. Jejunal and ileal permeability (as assessed by the passive uptake of L-glucose, tissue conductance, and mucosal-to-serosal flux of [3H]inulin) was increased in animals treated with HD-Rap or HD-Rap/CsA, when compared with CsA or controls. These parameters of permeability were no different at lower doses of Rap or Rap/CsA. The jejunal and ileal villous surface area was increased in CsA, but decreased in HD-Rap or HD-Rap/CsA animals. Thus, HD-Rap given alone or in combination with CsA reduced body weight gain, in part due to reduced food intake and malabsorption of lipids, which was due at least in part to reduced intestinal surface area. The relevance of these findings to patients undergoing chronic immunosuppressive drug therapy needs to be established.     

Early modifications of chemokine production and mRNA expression during rush venom immunotherapy

The mechanism by which specific immunotherapy exerts its beneficial effect remains unclear. Chemokines are implicated in inflammatory and allergic diseases, in particular via their ability to induce histamine release from basophils, a potential early target of rush venom immunotherapy (RVIT), In this study, the authors evaluated ex vivo regulated upon activation normal T-cell expressed and secreted (RANTES), interleukin 8 (IL-8) and monocyte chemoattractant protein 1 (MCP-1) production and mRNA expression by mononuclear cells (MNC) from nine patients undergoing a 3.5-h ultra rush treatment, before treatment at Day 0 (D0), at the end of the 3.5-h of the rush at Day 4h (D4h), at Day 15 (D15) and Day 45 (D45) after treatment. Increased RANTES release and mRNA expression were observed in 24-h culture of peripheral blood MNC collected at D4h. This was followed by a decrease in the production of RANTES, IL-8 and MCP-1, 45 days after initiation of RVIT. The same pattern was observed after in vitro venom stimulation of MNC. At the mRNA level, similar profiles were observed except for IL-8 mRNA which inversely increased during RVIT. These results suggest that RVIT is associated with a general decrease in chemokines which may explain, in part, the clinical efficacy of specific immunotherapy.     

The surface of Toxoplasma tachyzoites is dominated by a family of glycosylphosphatidylinositol-anchored antigens related to SAG1

Toxoplasma gondii is an Apicomplexan parasite with a complex life cycle that includes a rapidly dividing asexual stage known as the tachyzoite. The tachyzoite surface has been reported to comprise five major antigens, the most abundant of which is designated SAG1 (for surface antigen 1). At least one of the other four (SAG3) and another recently described minor antigen (SRS1 [for SAG1-related sequence 1]) have previously been shown to be structurally related to SAG1. To determine if further SAG1 homologs exist, we searched a Toxoplasma expressed sequence tag (EST) database and found numerous ESTs corresponding to at least three new genes related to SAG1. Like SAG1, these new SRS genes encode apparently glycosylphosphatidylinositol-anchored proteins that share several motifs and a set of conserved cysteine residues. This family appears to have arisen by divergence from a common ancestor under selection for the conservation of overall topology. The products of two of these new genes (SRS2 and SRS3) are shown to be expressed on the surface of Toxoplasma tachyzoites by immunofluorescence. We also identified strain-specific differences in relative expression levels. A total of 10 members of the SAG1 gene family have now been identified, which apparently include three of the five major surface antigens previously described and one antigen expressed only in bradyzoites. The function of this family may be to provide a redundant system of receptors for interaction with host cells and/or to direct the immune responses that limit acute T. gondii infections.     

Development of technologies aiding large-tissue engineering

Apoptosis associated oligonucleosomal fragmentation of DNA can result from the activation of endonucleases that exhibit different pH optima and are either sensitive or insensitive to divalent cations. DNA fragmentation due to activation of cation sensitive endonucleases occurs in the absence of a change in intracellular pH whereas intracellular acidification is a feature of apoptosis characterized by activation of cation insensitive acidic endonuclease. We have reported earlier that somatostatin (SST) induced DNA fragmentation and apoptosis is signaled in a receptor subtype selective manner uniquely via human somatostatin receptor subtype 3 (hSSTR3). In the present study we investigated the pH dependence and cation sensitivity of endonuclease induced in hSSTR3 expressing CHO-K1 cells by the SST agonist octreotide (OCT) and its effect on intracellular pH. We show that OCT induced apoptosis is associated with selective stimulation of a divalent cation insensitive acidic endonuclease. The intracellular pH of of cells undergoing OCT induced apoptosis was 0.9 pH units lower than that of control cells. The effect of OCT on endonuclease and pH was inhibited by orthovanadate as well as by pretreatment with pertussis toxin, suggesting that hSSTR3 initiated cytotoxic signaling is protein tyrosine phosphatase mediated and is G protein dependent. These findings suggest that intracellular acidification and activation of acidic endonuclease mediate wild type p53 associated apoptosis signaled by hormones acting via G protein coupled receptors.