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Hot Plate (hot + plate)
Selected AbstractsProliferation patterns of cervical cells as visualized in Leiden liquid cytology slidesDIAGNOSTIC CYTOPATHOLOGY, Issue 1 2004Laura Luzzatto M.D. Abstract The Leiden liquid-based cytology method for the preparation of optimal cytological slides is reported. In such slides, the proliferation pattern of cervical cells can be visualized in detail. Cervical smears and suspension preparations of 665 consecutive unselected patients received in 2003 were studied. Of the 665 patients, 26 (10 normal, 10 with cervical atrophy, 5 with mild dysplasia, and 1 carcinoma in situ) were selected. After using the Thermo Shandon Papspin, the wet slides were placed on a hot plate and dried for 30 min. Proliferation of the cervical cells was visualized in brown by staining the cells for MiB-1 antigen, and nuclear DNA in blue by a standardized short staining with hematoxylin. We found excellent high-resolution demonstrability of cell cycle-related MiB-1 distribution in the well-flattened nuclei. The phase of the cell cycle could be deduced from brown-blue staining patterns. There was a significant increase of MiB-1-positive cell yield related to progression in the degree of pathology. Diagn. Cytopathol. 2004;31:5,9. © 2004 Wiley-Liss, Inc. [source] Dry film microchips for miniaturised separationsELECTROPHORESIS, Issue 24 2009Rosanne M. Guijt Abstract In this work microfluidic devices were made from the dry film photoresist Ordyl SY330, characterised by optical and electron microscopy and used for electrophoretic separations. A simple and fast microfabrication process was developed for the fabrication of channels that are 50,,m wide and 30,,m in height, requiring only the use of an office laminator, a hot plate, an exposure source and mask and an electric drill to make four microdevices in less than 1,h. The optical properties of the photoresist were studied and the resist showed significant absorbance below 370,nm and 570,630,nm, and had an optical transmission of 80% between 400 and 550,nm. Fluorescence emission over the region of maximum transmission was low allowing these devices to be used for fluorescence detection at 488/512,nm. Electrophoretic separation of APTS and three derivatised sugars was performed in 20,mM phosphate buffer, pH 2.5 with efficiencies of the three sugars of 40,000 plates (2,100,000,plates/m) within 30,s at a field strength of 500,V/cm. The simple fabrication process also allowed microchannels to be easily filled with chromatography particles before sealing, avoiding the challenging task of slurry packing, and the potential of these devices for liquid chromatography was demonstrated by the extraction of fluorescein onto anion exchange particles. [source] Tolerance to non-opioid analgesics in PAG involves unresponsiveness of medullary pain-modulating neurons in male ratsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 6 2009Victor Tortorici Abstract Opiate analgesia can be hampered by a reduction in pharmacological effectiveness (tolerance), and this crucially depends on the periaqueductal gray matter (PAG). Non-opioids like metamizol (dipyrone) or aspirin also induce PAG-dependent analgesia and tolerance, but the neuronal bases of this tolerance are unknown. Metamizol is a pyrazolon derivative and cyclooxygenase inhibitor with widespread use as an analgesic in Europe and Latin America. Metamizol was microinjected into the PAG of awake male rats, and antinociception was assessed by the tail flick (TF) and hot plate (HP) tests. Microinjection twice daily for 2.5 days caused tolerance to metamizol. The rats were then anesthetized and recordings from pain-facilitating on-cells and pain-inhibiting off-cells of the rostral ventromedial medulla (RVM) were performed. PAG microinjection of morphine or metamizol depresses on-cells, activates off-cells and thus inhibits nociception, including TF and HP. In metamizol-tolerant rats, however, PAG microinjection of metamizol failed to affect on- or off-cells, and this is interpreted as the reason for tolerance. In metamizol-tolerant rats morphine microinjection into PAG also failed to affect RVM neurons or nociception (cross-tolerance). In naïve, non-tolerant rats the antinociceptive effect of PAG-microinjected metamizol or morphine was blocked when CTOP, a ,-opioid antagonist, was previously microinjected into the same PAG site. These results emphasize a close relationship between opioid and non-opioid analgesic mechanisms in the PAG and show that, like morphine, tolerance to metamizol involves a failure of on- and off-cells to, respectively, disfacilitate and inhibit nociception. Cross-tolerance between non-opioid and opioid analgesics should be important in the clinical setting. [source] Neuronal cell adhesion molecule deletion induces a cognitive and behavioral phenotype reflective of impulsivityGENES, BRAIN AND BEHAVIOR, Issue 4 2008L. D. Matzel Cell adhesion molecules, such as neuronal cell adhesion molecule (Nr-CAM), mediate cell,cell interactions in both the developing and mature nervous system. Neuronal cell adhesion molecule is believed to play a critical role in cell adhesion and migration, axonal growth, guidance, target recognition and synapse formation. Here, wild-type, heterozygous and Nr-CAM null mice were assessed on a battery of five learning tasks (Lashley maze, odor discrimination, passive avoidance, spatial water maze and fear conditioning) previously developed to characterize the general learning abilities of laboratory mice. Additionally, all animals were tested on 10 measures of sensory/motor function, emotionality and stress reactivity. We report that the Nr-CAM deletion had no impact on four of the learning tasks (fear conditioning, spatial water maze, Lashley maze and odor discrimination). However, Nr-CAM null mice exhibited impaired performance on a task that required animals to suppress movement (passive avoidance). Although Nr-CAM mutants expressed normal levels of general activity and body weights, they did exhibit an increased propensity to enter stressful areas of novel environments (the center of an open field and the lighted side of a dark/light box), exhibited higher sensitivity to pain (hot plate) and were more sensitive to the aversive effects of foot shock (shock-induced freezing). This behavioral phenotype suggests that Nr-CAM does not play a central role in the regulation of general cognitive abilities but may have a critical function in regulating impulsivity and possibly an animal's susceptibility to drug abuse and addiction. [source] Extraction Using Moderate Electric FieldsJOURNAL OF FOOD SCIENCE, Issue 1 2004I. SENSOY ABSTRACT: During moderate electric field (MEF) processing, a voltage applied across a food material may affect the permeability of cell membranes. It is known that high electric fields can cause either reversible or irreversible rupture of cell membranes. In this research, the effect of MEF processing on permeability was studied. Effects of frequency and electric field strength were investigated. Cellular structure was investigated by transmission electron microscopy (TEM). Fermented black tea leaves and fresh or dry mint leaves were placed in tea bags or cut in 1 cm2 squares, depending on the experiment, and immersed in an aqueous fluid medium. Control samples were heated on a hot plate. MEF treatments were conducted by applying a voltage across electrodes immersed in opposite sides of the beaker. Control and MEF-treated fresh mint leaf samples heated to 50°C were analyzed by TEM. MEF processing significantly increased the extraction yield for fresh mint leaves because of additional electric field effects during heating. Dried mint leaves and fermented black tea leaves were not affected by the treatment type. Low frequency resulted in higher extraction rates for fresh mint leaves. The electric field strength study showed that electrical breakdown is achieved even at low electric field strengths. MEF treatment shows potential to be used as an alternative to conventional heating for extraction from cellular materials. [source] Antinociceptive efficacy of levetiracetam in a mice model for painful diabetic neuropathyACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 7 2008M. OZCAN Background and Objective: Despite important advances in available knowledge, management of neuropathic pain remains incomplete, and results from experimental and clinical studies indicate that some anticonvulsants show promise for treating neuropathic pain. The aim of this study was to assess the antinociceptive efficacy of levetiracetam (LEV, ucb L059) in a mice model for painful diabetic neuropathy using the in vivo nociceptive behavioral ,hot-plate test.' Methods: The hot-plate test consisted of placing individual mice (adult male Balb/C) on the hot plate at 50±0.1 °C and timing the delay for the first hind paw lift (nociceptive threshold). After obtaining control values, diabetes was induced by injection of streptozotocin [200 mg/kg intraperitoneally (i.p.)] and 2 weeks after induction of diabetes (serum glucose ,400 mg/dL) LEV was administered i.p. and hot-plate tests were repeated. Pain threshold values were determined and analyzed by Kruskal,Wallis one-way analysis of variance (ANOVA) followed by a pairwise comparison using a Dunnett's t -test on the ranked data. Results: LEV (60, 300 and 900 mg/kg) had no significant effect on the nociceptive threshold in normal mice (n=8 for each dose, P>0.05). There were significant decreases in pain threshold latency in diabetic mice compared with the normal healthy group and these were significantly and dose-dependently restored by much lower doses of LEV (20, 100 and 200 mg/kg) in a reversible manner. Conclusion: Results obtained from the in vivo behavioral test lend support to the validation of the promising therapeutic potential of the novel antiepileptic agent LEV in the treatment of neuropathic pain. [source] Antipyretic and analgesic activities of Caesalpinia bonducella seed kernel extractPHYTOTHERAPY RESEARCH, Issue 5 2005P. Archana Abstract Ethanolic extract (70%) of Caesalpinia bonducella seed kernel has been subjected for its antipyretic and antinociceptive activities in adult albino rats or mice of either sex at 30, 100 and 300 mg/kg orally. The extract demonstrated marked antipyretic activity against Brewer's yeast-induced pyrexia in rats. The extract had significant central analgesic activity in hot plate and tail flick methods. It also exhibited marked peripheral analgesic effect in both acetic acid-induced writhing test in mice and Randall-Selitto assay in rats. It also significantly inhibited the formalin-induced hind paw licking in mice. In conclusion, the present study suggests that the ethanolic extract of Caesalpinia bonducella seed kernel possesses potent antipyretic and antinociceptive activities and thus, validates its use in the treatment of pain and pyretic disorders. Copyright © 2005 John Wiley & Sons, Ltd. [source] Morphology profiles generated by temperature gradient in PMMA modified epoxy systemPOLYMER ENGINEERING & SCIENCE, Issue 11 2001P. M. Stefani A diglycidyl ether of bisphenol-A (DGEBA) epoxy resin was modified with 15 wt% of poly(methylmethacrylate) (PMMA) and cured with a stoichiometric amount of 4,4,-diamino diphenyl methane (DDM). The reactive mixture was cured in a heated mold with different gradients of temperature. Temperature profiles in the mold were imposed by generation of a heat flux from the base, supported on a hot plate, and the top, cooled with water; they were measured along the mold. Depending on the thermal history in each position of the mold, the competition between the phase-separation process and reaction kinetics produces opaque or transparent zones. Phase separation can also occur in the postcure process while the gelation does not take place before. Therefore, a thermoset plate with gradient of morphology and properties was obtained. Mass fractions of PMMA dissolved in the matrix were calculated with the Fox equation from glass transition temperatures measured along the mold. They were related to morphologies developed during curing. The superposition of the phase diagrams with the conversion-temperature trajectories during cure permitted an explanation of the morphology gradients generated. [source] Stress-Induced Analgesia and Morphine Responses Are Changed in Catechol- O -methyltransferase-Deficient Male MiceBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 4 2008Oleg Kambur It is not clear how the effects of COMT are mediated and only few relevant animal studies have been performed. Here, we used old male Comt gene knock-out mice as an animal model to study the effects of COMT deficiency on nociception that was assessed by the hot plate and tail flick tests. Stress-induced analgesia was achieved by forced swim. Morphine antinociception was measured after 10 mg/kg of morphine subcutaneously. Morphine tolerance was produced with subcutaneous morphine pellets and withdrawal provoked with subcutaneous naloxone. In the hot plate test, morphine-induced antinociception was significantly greater in the COMT knock-out mice, compared to the wild-type mice. This may be due to increased availability of opioid receptors as suggested by previous human studies. In the tail flick test, opioid-mediated stress-induced analgesia was absent and morphine-induced analgesia was decreased in COMT knock-out mice. In the hot plate test, stress-induced analgesia developed to all mice regardless of the COMT genotype. There were no differences between the genotypes in the baseline nociceptive thresholds, morphine tolerance and withdrawal. Our findings show, for the first time, the importance of COMT activity in stress- and morphine-induced analgesia in mice. COMT activity seems to take part in the modulation of nociception not only in the brain, as suggested earlier, but also at the spinal/peripheral level. [source] New potent and selective inhibitors of anandamide reuptake with antispastic activity in a mouse model of multiple sclerosisBRITISH JOURNAL OF PHARMACOLOGY, Issue 1 2006Alessia Ligresti We previously reported that the compound O-2093 is a selective inhibitor of the reuptake of the endocannabinoid anandamide (AEA). We have now re-examined the activity of O-2093 in vivo and synthesized four structural analogs (O-2247, O-2248, O-3246, and O-3262), whose activity was assessed in: (a) binding assays carried out with membranes from cells overexpressing the human CB1 and CB2 receptors; (b) assays of transient receptor potential of the vanilloid type-1 (TRPV1) channel functional activity (measurement of [Ca2+]i); (c) [14C]AEA cellular uptake and hydrolysis assays in rat basophilic leukaemia (RBL-2H3) cells; (d) the mouse ,tetrad' tests (analgesia on a hot plate, immobility on a ,ring', rectal hypothermia and hypolocomotion in an open field); and (e) the limb spasticity test in chronic relapsing experimental allergic encephalomyelitis (CREAE) mice, a model of multiple sclerosis (MS). O-2093, either synthesized by us or commercially available, was inactive in the ,tetrad' up to a 20 mg kg,1 dose (i.v.). Like O-2093, the other four compounds exhibited low affinity in CB1 (Ki from 1.3 to >10 ,M) and CB2 binding assays (1.3 Modulation of ultraviolet-induced hyperalgesia and cytokine upregulation by interleukins 10 and 13BRITISH JOURNAL OF PHARMACOLOGY, Issue 7 2000Nayef E Saadé Exposure to midrange ultraviolet radiation (UVB) is known to produce skin inflammation similar to sunburn. The aim of this study was to characterize the hyperalgesia and cytokine upregulation induced by UVB and their modulation by antiinflammatory cytokines. Acute exposure of the dorsal skin of mice to UVB (200, 250 and 300 mJ cm2) resulted in a dose-dependent decrease in the latencies of the hot plate and tail flick tests, without evident signs of skin lesions. The observed hyperalgesia displayed a biphasic temporal evolution with an acute phase (3,6 h) and a late (48,96 h) phase. Exposure to UVB (300 mJ cm2) elicited significant upregulation of interleukin (IL)-1,, tumour necrosis factor (TNF)-, and nerve growth factor (NGF), determined by ELISA in the exposed skin. This upregulation was more important during the acute phase of hyperalgesia. Daily treatment of mice, with i.p. injections of either IL-10 or IL-13 (1.5, 7.5 and 15 ng in 100 ,l saline) produced a dose-dependent attenuation of the UVB-induced hyperalgesia. Treatment with the highest doses of either IL-10 or IL-13, produced significant attenuation of the levels of the cytokines and NGF by UVB, with relatively more pronounced effects by IL-13. Acute exposure to moderate amounts of UVB results in a systemic hyperalgesia related to the upregulation of cytokine and NGF levels, since both were prevented by treatment with antiinflammatory cytokines. British Journal of Pharmacology (2000) 131, 1317,1324; doi:10.1038/sj.bjp.0703699 [source] Factors affecting wafer sheet qualityINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 5 2006Ismail S. Dogan Summary Wafers are low-moisture-baked foods. They are formed from a batter and baked between hot plates. The quality of wafer sheets is mainly controlled by flour property, water level and temperature, mixing action, baking time and temperature. The quality is judged by attributes of the batter such as the density, viscosity, holding time and temperature, and by properties of the wafer such as weight, surface colour, fragility and moisture content. In this study, the batter-specific gravity of 1.11,1.19 was recorded. Water and gluten content did not affect density. Water level, but not gluten content, however affected viscosity. Batter holding time drastically changed viscosity. The temperature of plates did significantly affect bake time. For wafer sheets with a high quality, 155,165% water level, 170 °C baking temperature and 2 min of bake time were found to be adequate. Wafer sheets baked at the lower temperatures stuck to the plates and broke up to several pieces. At a lower water level (<145%) and baking temperature of 150 °C, tough and flinty sheets were obtained, whereas at a water level higher than 160% and a higher temperature (190 °C), fragile sheets were obtained. [source]
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