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Difference images calculated from ictal and interictal technetium-99m-HMPAO SPECT scans of epilepsy.

UNLABELLED: Image processing techniques were applied to SPECT brain images to aid in the localization of epileptic foci. METHODS: Ictal and interictal cerebral perfusion SPECT images were acquired from 12 epilepsy patients (6 temporal, 6 extratemporal) after injection of 20 mCi 99mTc-HMPAO. Each ictal scan was registered to the same patient's interictal scan. Normalization of the three-dimensional data was applied to account for global percent brain uptake and total injected activity. After registration, normalization and subtraction of the SPECT images and functional difference images were computed. Difference images were calculated, which give a quantitative measure of perfusion alterations during ictus. The resulting difference images were also registered with each patient's MRI scan which permits localization of perfusion changes onto anatomical structures. RESULTS: Areas in the brain where significant perfusion increases occur correlate with areas confirmed to be seizure foci. Four of the six patients with known temporal lobe seizure foci exhibited significant perfusion increases on the difference images. These areas demonstrate a percent increase of perfusion larger than 40%. For the extratemporal seizure patients, four of the four confirmed seizure sites were diagnosed with difference images. Results on the remaining two patients were inconclusive. CONCLUSION: When compared to side-by-side visual interpretation of the ictal and interictal SPECT images, registration of SPECT and MR images together with calculated difference maps greatly enhances the ability to localize epileptic seizure foci. This offers the potential to locate epileptic seizure foci using a noninvasive, inexpensive imaging procedure and data processing algorithm.

Adolescent↗

NG-nitro-L-arginine methyl ester attenuates the maintenance and expression of methamphetamine-induced behavioral sensitization and enhancement of striatal dopamine release.

We examined the roles of nitric oxide (NO) in methamphetamine (MAP)-induced behavioral sensitization and enhancement of striatal dopamine (DA) release using both in vivo and in vitro methods. Repeated administration of MAP produced augmentation of MAP-induced locomotor activity after 3-day withdrawal of MAP and an enhancement of MAP-evoked DA release from striatal slices after 6-day withdrawal. When the NO synthase (NOS) inhibitor NG-nitro-L-arginine methyl ester (L- NAME) was administered only during the period of MAP withdrawal, the behavioral sensitization and enhancement of DA release were attenuated significantly. In contrast, NG-nitro-D- arginine methyl ester, an inactive isomer of L-NAME, exhibited no such effect. When L-NAME was administered acutely before the challenge injection of MAP, behavioral sensitization was also attenuated only when the dose of L-NAME was high. Coadministration of L-NAME with MAP did not block the development of sensitization to MAP. We also examined whether MAP-induced behavioral sensitization and enhancement of DA release could be observed in vivo in a microdialysis experiment. Challenge injection of MAP caused marked enhancement of DA release in MAP-sensitized rats compared with saline-treated controls corresponding to robust augmentation of locomotor activity. When L-NAME was injected during the MAP withdrawal period, the enhancement of DA release and locomotor activity induced by challenge injection of MAP were attenuated. These results suggest that NO production plays a role in the maintenance (expression) of MAP-induced behavioral sensitization and enhancement of DA release but not in the development of these effects.

Animals↗

A myeloid-lineage-specific enhancer upstream of the mouse myeloperoxidase (MPO) gene.

The myeloperoxidase (MPO) gene is selectively expressed during haemopoiesis in the granulocytic lineage. Compared with the erythroid (beta-globin) and B-cell (immunoglobulin) lineages, little is known of the regulatory sequences and transcription factors involved in the regulation of genes specific for granulopoiesis. We have approached this issue by identifying a strong enhancer for the murine MPO gene. A candidate enhancer region was mapped by the detection of a strong DNase I hypersensitive site, -3.4 to -3.2 kb upstream of the MPO gene. A 301 bp fragment encompassing the DNase I site was shown to have strong enhancer function in a transient assay following transfection of a reporter gene into a MPO-expressing cell (WEHI 3BD+), but was inactive in lymphoid cells. Analysis of sub-fragments revealed that the whole 301 bp fragment is required for maximal enhancer function.

Animals↗

Effects of methamphetamine administration on brain neurotensin-like immunoreactivity in rats.

The effects of methamphetamine (MAP) administration on neurotensin-like immunoreactivity (NTLI) were investigated in the rat brain. A single administration of MAP induced dose-dependent and reversible increases in NTLI in the caudate-putamen, limbic forebrain and midbrain. NTLI in the caudate-putamen, limbic forebrain and midbrain was also enhanced after repeated administration of MAP. It was assumed that MAP enhanced NTLI in the caudate-putamem, limbic forebrain and midbrain through its action upon the nigrostriatal and mesolimbic dopamine systems.

Animals↗

Reduction of rat striatal thyrotropin-releasing hormone receptors produced by repeated methamphetamine administration.

It has been reported previously that repeated, but not continuous, administration of methamphetamine (MAP) to animals produces progressive and sustained enhancement of MAP-induced behavior (behavioral sensitization), which may be related to functional changes in central dopamine (DA) systems. To investigate the possible involvement of thyrotropin-releasing hormone (TRH), a neuromodulator of DA, both immunoreactive TRH (IR-TRH) levels and specific TRH binding were examined in rat brain regions after MAP administration either repeatedly (4 mg/kg intraperitoneally once a day for 14 consecutive days) or continuously (about 4 mg/kg/day for 13 consecutive days). Although no significant changes were observed in IR-TRH levels in any regions of the brain following repeated MAP injections, specific TRH binding in the striatum significantly decreased. Scatchard analysis revealed that the decrease was due to a reduction in the maximum number of binding sites (Bmax). Pretreatment with haloperidol prior to each MAP injection prevented this decrease. Continuous MAP administration had no effect on regional specific TRH binding. These results suggest that repeated MAP administration caused lasting dysfunction in the brain TRH system, which may be implicated in the behavioral sensitization.

Animals↗

Affinity maps and relationship diagrams: two tools to enhance performance improvement.

This article describes two performance improvement tools: an affinity map and a relationship diagram. The author suggests when to use them and provides instructions on how to scan the environment of a nursing unit to discover problems, organize ideas about the problem, and find the root cause and effect of the relationship among staff's ideas about the problem. When the main cause and effect of a problem are known, management and staff can decide where to direct their process improvement efforts.

Audiovisual Aids↗

Enhancement of ambulation-increasing effect produced by repeated administration of methamphetamine in rats and neurochemical changes in catecholaminergic neurons.

Male rats of the Wistar strain were repeatedly given methamphetamine (MAP) at 0.5 mg/kg, s.c., 10 times at a fixed interval of 4 days in different environmental situations. The effects of MAP administration on ambulatory activity and neurochemical parameters in the brain were investigated. MAP (0.5 mg/kg) markedly increased ambulatory activity. The ambulation-increasing effect of MAP was progressively enhanced without accompanying stereotyped behaviors when the drug was repeatedly given in the activity cage. The once enhanced effect was considered to be irreversible. In addition, the pretreatment with MAP in the activity cage produced a decrease in the maximum density of 3H-spiperone binding sites in the striatum and that of 3H-WB4101 binding sites in the cortex and hippocampus, with decreases in catecholamine and increases in its metabolites. However, the enhancement of the ambulation-increasing effect of MAP and changes in the binding sites or catecholamine metabolism were scarcely observed when the drug was repeatedly given to the rats in the narrow cage where horizontal ambulation of the animals was strongly impaired. These results suggest that the enhancing effect of MAP is closely related to the environmental situations to which the animals have been exposed to under the drug effect. Moreover, it is indicated that there is a correlation between the enhancement of the ambulation-increasing effect of MAP and changes in the neurochemical parameters. The enhancing effect of MAP is supposed to have been partially caused by changes in cerebral catecholaminergic systems, in particular an increase in catecholamine turnover.

Animals↗

MAP kinase phosphatase 1 is expressed and enhanced by FK506 in surviving mamillary, but not degenerating nigral neurons following axotomy.

The MAP kinase phosphatase 1 (MKP-1), a dual serine-threonine phosphatase, inactivates the MAP kinases ERK and JNK/SAPK which are involved in neuronal survival and neuronal cell death following injury and degenerative stimuli. We have studied by immunocytochemistry whether regulation of MKP-1 is part of the cell-body response following nerve fiber transection. The expression of MKP-1 was investigated in axotomized neurons of the corpus mamillaris (CMm) and substantia nigra pars compacta (SNC) following transection of the mamillo-thalamic tract (MT) and the medial forebrain bundle (MFB), respectively. In contrast to the surviving CMm neurons, the vast majority of SNC neurons undergoes cell death following axotomy. MKP-1 immunoreactivity which is absent in untreated adult rats, appeared in CMm neurons 24 h following MT transection, reached a maximum after 2 days and persisted in a substantial proportion of CMm neurons until 20 days, the end of observation period. In contradistinction, MKP-1 could not be detected in the SNC neurons. MKP-1 immunoreactivity was virtually restricted to the nuclei of neurons. Subcutaneous injection of the immunosuppressant FK506 that protects axotomized SNC neurons against neuronal cell death, enhanced the expression of MKP-1 in CMm, but failed to do so in SNC neurons. The selective expression of MKP-1 in CMm is the first finding on a different regulation of components in the stress kinase signal pathway in surviving vs. degenerating axotomized neurons.

Animals↗

Role of Cx43 phosphorylation and MAP kinase activation in EGF induced enhancement of cell communication in human kidney epithelial cells.

Epidermal growth factor (EGF) has been found to induce enhanced gap junctional intercellular communication (GJIC) in the human kidney epithelial cell line K7. This is in contrast to what is reported for other cell types, which all show decreased GJIC in response to EGF. In the present study it is shown that 12-O-tetradecanoylphorbol-13-acetate (TPA) and EGF induce similar phosphorylation pattern of the gap junction protein connexin43 (Cx43) in K7 cells, although their effects on GJIC are opposite. Tyrosine phosphorylation of a 42 kD protein was observed to be induced concomitantly with phosphorylation of Cx43. EGF was however found to induce only serine phosphorylation of Cx43, indicating that the tyrosine kinase activity of the EGF receptor was not directly affecting the gap junction protein. The 42 kD protein phosphorylated on tyrosine was identified to be a mitogen activated protein (MAP) kinase. Both EGF and TPA was found to activate MAP kinase in these cells. Phosphorylation of Cx43 and enhancement of GJIC in response to EGF occurred with difference in time course. Phosphorylation of Cx43 was completed within 15 min, while the enhanced GJIC appeared 2-3 h later. It is therefore possible that regulation of synthesis or transport of Cx43 is responsible for the increase in GJIC, rather than direct involvement of Cx43 phosphorylation. This is in support of our previous finding that protein synthesis is necessary for EGF induced upregulation of GJIC in K7 cells.

Antibodies↗

Regulation of nitric oxide production in cultured human T84 intestinal epithelial cells by nuclear factor-kappa B-dependent induction of inducible nitric oxide synthase after exposure to bacterial endotoxin.

BACKGROUND: Intestinal epithelium is consistently in contact with lipopolysaccharide (LPS) produced by intraluminal microbes. LPS induces nitric oxide production in many rodent cells, but in human cells it is very differently regulated. AIM: To test the hypothesis that exposure to LPS up-regulates nitric oxide synthesis in human intestinal epithelium. METHODS AND RESULTS: LPS induced nitric oxide synthesis in T84 cells in a time- and dose-dependent manner whereas detectable amounts of peroxynitrite were not produced. A novel selective inducible nitric oxide synthase (iNOS) inhibitor 1400 W potently inhibited LPS-induced nitric oxide synthesis in T84 cells while dexamethasone was relatively ineffective. Nitric oxide production was sensitive to cycloheximide, indicating that it was dependent on de novo protein synthesis. Nuclear factor-kappa B (NF-kappa B) inhibitor pyrrolidinedithiocarbamate abolished iNOS and nitric oxide production. Nitric oxide synthesis was also suppressed by genistein (tyrosine kinase inhibitor) and PD 98059 (p44/42 MAP kinase inhibitor) but enhanced by SB 203580 (p38 MAP kinase inhibitor). CONCLUSIONS: Intestinal epithelial cells express iNOS and produce nitric oxide in a nuclear factor-kappa B-dependent manner when exposed to LPS. The process is regulated by tyrosine kinases, and p44/42 and p38 MAP kinases. Because nitric oxide acts as an antimicrobial agent and immune modulator, these findings are implicated in the regulation of gut mucosal immunity.

Amidines↗

The Wnt-1 proto-oncogene regulates MAP kinase activation by multiple growth factors in PC12 cells.

PC12/Wnt-1 cells display morphological changes in response to stimulation by select growth factors but do not respond to NGF. Furthermore, stimulation by EGF can induce neuronal differentiation in these cells but not in wild type cells. We have found that in these cells, compared to wild type PC12 cells, FGF and EGF stimulation of MAP kinase activity is enhanced, while NGF stimulation of MAP kinase in diminished. Finally, in cells expressing Wnt-1, the effect of cyclic adenosine monophosphate (cAMP) on MAP kinase activation is reversed; cAMP stimulates MAP kinase in wild type PC12 cells but inhibits MAP kinase in PC12/Wnt-1 cells. These data suggest that Wnt-1 expression alters the specificity of growth factor signaling in neuronal cells.

Animals↗

Mitogenic synergy through multilevel convergence of hepatocyte growth factor and interleukin-4 signaling pathways.

Hepatocyte growth factor (HGF) regulates various physiological and developmental processes in concert with other growth factors, cytokines and hormones. We examined interactions between cell signaling events elicited by HGF and the cytokine interleukin (IL)-4, in the IL-3-dependent murine myeloid cell line 32D transfected with the human HGF receptor, c-Met. HGF was a potent mitogen in these cells, and prevented apoptosis in response to IL-3 withdrawal. IL-4 showed modest anti-apoptotic activity, but no significant mitogenic activity. IL-4 synergistically enhanced HGF-stimulated DNA synthesis, whereas only additive prevention of apoptosis was observed. IL-4 did not enhance HGF-dependent tyrosine phosphorylation of c-Met or Shc. In contrast, HGF-stimulated activation of MAP kinases was enhanced by IL-4, suggesting that the IL-4 and HGF signaling pathways converge upstream of these events. Although phosphatidylinositol 3-kinase (PI3K) inhibitors diminished HGF-induced mitogenesis, anti-apoptosis, and MAP kinase activation, IL-4 enhanced HGF signaling persisted even in the presence of these inhibitors. IL-4 enhancement of HGF signaling was partially blocked in 32D/c-Met cells treated with inhibitors of MEK1 or c-Src kinases, completely blocked by expression of a catalytically inactive mutant of Janus kinase 3 (Jak3), and increased in 32D/c-Met cells overexpressing STAT6. Our results suggest that the IL-4 and HGF pathways converge at multiple levels, and that IL-4-dependent Jak3 and STAT6 activities modulate signaling events independent of PI3K to enhance HGF-dependent mitogenesis in myeloid cells, and possibly other common cellular targets.

Adaptor Proteins, Signal Transducing↗

Cloning of a human homolog of the Drosophila enhancer of zeste gene (EZH2) that maps to chromosome 21q22.2.

To identify genes that map on human chromosome 21 (HC21) and that may contribute to the phenotype of Down syndrome (DS), exon trapping was applied to cosmid DNA from an HC21-specific library LL21NCO2-Q. More than 550 potential exons were cloned and partially characterized. One of these, hmc23b04 (GenBank X88270) showed strong homology to the Drosophila Enhancer of zeste protein (GenBank U00180) from amino acid 665 to 694 (p = 7.6 x 10(-11). We have cloned the full-length cDNA for this human homolog of the Drosophila E(z) gene (termed EZH2) and mapped it to within YACs 64f11 and 809b11 between markers D21S65 and ERG on human chromosome 21q22.2. Sequence analysis indicates that EZH2 encodes a 746-amino-acid polypeptide that shows 60.5% identity to the Drosophila E(z) protein and contains a trithorax-like domain and a DNA-binding motif. Northern blot analysis revealed that EZH2 is expressed in several tissues. Alternatively spliced mRNA species have been observed. The Drosophila E(z) protein is a member of the polycomb group genes that maintain homeotic gene repression and are thought to control gene expression by regulating chromatin. The strong sequence conservation suggests a possible function of EZH2 in regulation of gene transcription and chromatin structure; it may therefore contribute to certain phenotypes of Down syndrome by altered regulation of its target genes.

Alternative Splicing↗

Cerebral blood flow determination within the first 8 hours of cerebral infarction using stable xenon-enhanced computed tomography.

Cerebral blood flow mapping with stable xenon-enhanced computed tomography (Xe/CT) was performed in conjunction with conventional computed tomography (CT) within the first 8 hours after the onset of symptoms in seven patients with cerebral infarction. Six patients had hemispheric infarctions, and one had a progressive brainstem infarction. Three patients with very low (less than 10 ml/100 g/min) blood flow in an anatomic area appropriate for the neurologic deficit had no clinical improvement by the time of discharge from the hospital; follow-up CT scans of these three patients confirmed infarction in the area of very low blood flow. Three patients with moderate blood flow reductions (15-45 ml/100 g/min) in the appropriate anatomic area had significant clinical improvement from their initial deficits and had normal follow-up CT scans. One patient studied 8 hours after stroke had increased blood flow (hyperemia) in the appropriate anatomic area and made no clinical recovery.

Aged↗

A molecular marker map in 'Kanota' x 'Ogle' hexaploid oat (Avena spp.) enhanced by additional markers and a robust framework.

Molecular mapping of cultivated oats was conducted to update the previous reference map constructed using a recombinant inbred (RI) population derived from Avena byzantina C. Koch cv. Kanota x Avena sativa L. cv. Ogle. In the current work, 607 new markers were scored, many on a larger set of RI lines (133 vs. 71) than previously reported. A robust, updated framework map was developed to resolve linkage associations among 286 markers. The remaining 880 markers were placed individually within the most likely framework interval using chi2 tests. This molecular framework incorporates and builds on previous studies, including physical mapping and linkage mapping in additional oat populations. The resulting map provides a common tool for use by oat researchers concerned with structural genomics, functional genomics, and molecular breeding.

Avena↗

Epitope mapping and analysis of a growth-enhancing monoclonal antibody by limited tryptic digestion of porcine GH.

In this study, the epitope of a murine PS-7.6 monoclonal antibody (mAb) which was raised against the recombinant porcine GH (pGH) and subsequently shown to enhance the growth-promoting activity of pGH in a hypophysectomized rat model, was mapped by the limited tryptic digestion of pGH. A pGH fragment corresponding to amino acid residues 70-95 was separated by reverse-phase HPLC and also immunoprecipitated by PS-7.6 mAb. This fragment was found in an RIA to compete with radiolabelled pGH for the binding of PS-7.6 mAb in a dose-dependent fashion. Several peptides covering this potential epitope region of pGH(70-95) were synthesized and assayed by competitive RIA. The results suggested that pGH(75-90) was the optimal sequence recognized by PS-7.6 mAb. Sequential alanine substitution of each residue of pGH(75-90) revealed that the side chains of Leu76, Ile83 and Leu87 were critical for binding to PS-7.6 mAb. Other residues could be replaced by alanine without substantially altering the binding affinity. The region of amino acids 75-95 comprises the C-terminal end of the second helix of pGH and the repeating pattern of i and i + 3 (i + 7) of the critical amino acids appears consistent with PS-7.6 mAb binding to the hydrophobic side of the helix. The sequence and the helical structure of the epitope of PS-7.6 mAb provide the basis for designing the effective peptide vaccines to enhance the growth performance of animals.

Amino Acids↗

Signaling functions of L-selectin. Enhancement of tyrosine phosphorylation and activation of MAP kinase.

L-selectin is a leukocyte cell surface glycoprotein involved in carbohydrate-specific ligand binding which mediates rolling of leukocytes along endothelial surfaces. In addition to its role in adhesion, an intracellular signaling role for L-selectin has recently been recognized. In particular, cross-linking L-selectin leads to increased cytosolic Ca2+ levels and potentiation of the oxidative burst. As several cell surface glycoproteins have been shown to be linked to tyrosine kinases, we examined the hypothesis that L-selectin may be linked to pathways involving tyrosine phosphorylation in human neutrophils. Ligation of L-selectin by three different antibodies recognizing separate epitopes led to increased tyrosine phosphorylation of several cellular proteins as judged by anti-phosphotyrosine immunoblots of whole cell lysates with prominent bands at 40-42, 55-60, 70-72, and 105-120 kDa. The 42-kDa band comigrated with mitogen-activated protein (MAP) kinase as determined by immunoblotting with anti-MAP kinase antibody. This effect was specific for L-selectin, because antibodies against CD18, CD45, and CD10 did not increase tyrosine phosphorylation. Phosphorylation was not due to Fc binding, since F(ab')2 fragments of the anti-L-selectin antibodies were similarly effective, and the response was unaffected by Fc receptor blockade. Cross-linking of L-selectin was not required for enhanced tyrosine phosphorylation, because monovalent Fab fragments also increased tyrosine phosphorylation. The response to L-selectin antibodies was not inhibited by cytochalasin, suggesting that reorganization of the actin cytoskeleton was not required for this response. Sulfatides, sulfated glycolipids which may be natural ligands for L-selectin, also induced a rapid, dose-dependent increase in tyrosine phosphorylation. In addition, sulfatides, but not control glycolipids, resulted in enhanced tyrosine phosphorylation of MAP kinase. Both sulfatides and anti-L-selectin antibodies increased kinase activity of MAP kinase as determined by gel renaturation assay. The tyrosine kinase inhibitor, genistein, blocked the transient increase in intracellular Ca2+ and the oxidative burst induced by sulfatides, suggesting that this tyrosine phosphorylation is functionally important. We conclude that L-selectin is able to transmit intracellular signals, including increased tyrosine phosphorylation and activation of MAP kinase in neutrophils. We speculate that these events may contribute to the activation of neutrophils during adhesion.

Animals↗

Pressor and pulmonary responses to ET-1(1-31) in guinea-pigs.

1. Endothelin-1(1-31) (ET-1(1-31); 0.25 to 4 nmol kg(-1); i.v.) induced, in the guinea-pig, graded increases in MAP and an indomethacin-sensitive enhancement of pulmonary insufflation pressure (PIP). At all doses, ET-1(1-31) induced a monophasic pressor response, except at 4 nmol kg(-1), which caused a rapid and transient response (first phase: over first 10 min after injection) followed by a more slowly-developing and sustained (second phase: between 10 and 45 min after injection) increase in MAP. ET-1(1-31) was 4 to 10 fold less potent than ET-1 on PIP responses. 2. Phosphoramidon (5 and 10 mg kg(-1)) reduced both pressor and PIP effects of ET-1(1-31). Thiorphan (0.25 and 2.5 mg kg(-1)) did not affect the pressor responses to ET-1(1-31) although its PIP effects were markedly reduced by the NEP inhibitor. A selective endothelin-converting enzyme (ECE) inhibitor, CGS 35066 (1 mg kg(-1)), significantly reduced the second phase pressor response and increase in PIP triggered by ET-1(1-31). 3. The second (but not the first) pressor phase of ET-1(1-31) (4 nmol kg(-1)) was markedly reduced by BQ-123 (selective ET(A) antagonist), whereas the increase of PIP was significantly reduced by BQ-788 (selective ET(B) antagonist). Co-administration of BQ-123 plus BQ-788 abolished ET-1(1-31)-induced increase in PIP, but blockade of the second pressor phase afforded by BQ-123 was now reversed. 4. In guinea-pig isolated perfused lungs, ET-1(1-31) (50 nM) induced the release of prostacyclin and thromboxane A(2), which was inhibited by BQ-788 (5 nM) or thiorphan (25 microM), but not BQ-123 (1 microM). 5. These results suggest that ET-1(1-31) enhances MAP. Its sustained, but not transient, pressor effects are mediated via ET(A) receptor activation. Furthermore, ET-1(1-31) increases airway resistance in vivo and triggers prostacyclin and thromboxane A(2) release from perfused lungs predominantly via ET(B) receptor activation. ET-1(1-31) failed to display any selectivity of action towards either ET(A) or ET(B) receptors in these models. 6. We suggest that, in order to raise MAP, ET-1(1-31) requires conversion to ET-1, predominantly by ECE and to a lesser extent neutral endopeptidase 24.11, whereas the reverse holds true regarding its pharmacological effects in airways.

Analysis of Variance↗