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121.
AY Valeyev RA Cruciani GD Lange VS Smallwood JL Barker 《Canadian Metallurgical Quarterly》1993,155(2):199-203
Throughout the adult vertebrate central nervous system (CNS) gamma-aminobutyric acid (GABA) mediates transient Cl- conductances commonly identified as fast, Cl(-)-dependent inhibitory synaptic signals [Prog. Neurobiol., 36 (1991) 35-92]. In the rat hippocampus Cl(-)-dependent excitatory transients mediated by GABA emerge during the first postnatal week superimposed on a steady-state baseline that is also Cl(-)- and GABA-dependent [Int. J. Dev. Neurosci., 8 (1990) 481-490]. Here we report that many embryonic rat hippocampal neurons cultured for hours to days exhibit random fluctuations in Cl- channel activity that are mediated by continuous secretion of GABA in the absence of transients. Thus, GABA is broadcast tonically before it is released transiently. 相似文献
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Extent of motor unit activation during effort 总被引:2,自引:0,他引:2
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RW Niven KL Whitcomb L Shaner AY Ip OB Kinstler 《Canadian Metallurgical Quarterly》1995,12(9):1343-1349
PURPOSE: The objective of this study was to highlight differences in the pulmonary absorption of a monoPEGylated rhG-CSF and rhG-CSF after intratracheal instillation and aerosol delivery. METHODS: Male Sprague Dawley rats (250 g) were anesthetized and intratracheally instilled (IT) with protein solution or were endotracheally intubated and administered aerosol for 20 min via a Harvard small animal ventilator. A DeVilbiss "Aerosonic" nebulizer containing 5 ml of protein solution at approximately 3 mg/ml was used to generate aerosol. The volume of protein solution deposited in the lung lobes was estimated to be approximately 13 microliters after delivery of Tc-99m HSA solutions. The PEGylated proteins consisted of a 6 kDa (P6) or 12 kDa PEG (P12) linked to the N-terminus of rhG-CSF. rhG-CSF also was administered IT in buffers at pH 4 and pH 7 and in dosing volumes ranging from 100 to 400 microliters. Blood samples were removed at intervals after dosing and the total white blood cell counts (WBC) were determined. Plasma was assayed for proteins by an enzyme immuno assay. RESULTS: The plasma protein concentration v. time profiles were strikingly different for aerosol v. IT delivery. The Cmax values for rhG-CSF and P12 after aerosol delivery were greater than found after IT (Aerosol: 598 +/- 135 (ng/ml) rhG-CSF; 182 +/- 14 P12 v. IT: 105 +/- 12 rhG-CSF; 65.9 +/- 5 P12). Similarly, Tmax was reached much earlier after aerosol administration (Aerosol: 21.7 +/- 4.8 (min) rhG-CSF; 168 +/- 31 P12 v. IT: 100 +/- 17 rhG-CSF; 310 +/- 121 P12). Estimated bioavailabilities (F(lung)%) were significantly greater via aerosol delivery than those obtained after IT (Aerosol: 66 +/- 14 rhG-CSF; 12.3 +/- 1.9 P12 v. IT: 11.9 +/- 1.5 rhG-CSF; 1.6 +/- 0.1 P12). An increase in circulating WBC counts was induced by all proteins delivered to the lungs. The rate and extent of absorption of rhG-CSF was not influenced by the pH employed nor the instilled volume. CONCLUSIONS: Estimates of bioavailability are dependent upon the technique employed to administer drug to the lungs. Aerosol administration provides a better estimate of the systemic absorption of macromolecules. 相似文献
126.
Altered antigen presentation in mice lacking H2-O 总被引:1,自引:0,他引:1
M Liljedahl O Winqvist CD Surh P Wong K Ngo L Teyton PA Peterson A Brunmark AY Rudensky WP Fung-Leung L Karlsson 《Canadian Metallurgical Quarterly》1998,8(2):233-243
The phenomenon of transgenerational traumatization has currently become widely recognized and described, although the task of disentangling the underlying interactional mechanisms remains a difficult one. These transgenerational mechanisms were first detected in families of the survivors of the Holocaust, but they may be equally prominent in families of parents who have been traumatized in other ways, for example, as victims of child neglect and abuse, as orphaned children, or during military service. In cases in which parents have themselves been subjected to early parental deprivation, one or more children may become projectively identified with a parent's (posttraumatic) "bad child"-self, whereas the parent him/herself has identified with--enacts the role of--the idealized internal "martyr" parent. A case study is presented describing the individual and family therapeutic treatment of a woman who, as a child, had been traumatically separated from her parents. 相似文献
127.
Formation kinetics of hydroxymethylfurfural and brown coloured compounds in goat milk during heating
ONUR GÜNEŞER AYŞEGÜL KIRCA TOKLUCU YONCA KARAGÜL‐YÜCEER 《International Journal of Dairy Technology》2013,66(1):14-19
The formation of hydroxymethylfurfural, nonenzymatic brown coloured compounds and free sulphydryl groups in goat milk was studied during heating at 75–95 °C. Analysis of kinetic data suggested that formation of hydroxymethylfurfural and nonenzymatic brown coloured compounds followed zero order reaction kinetics, while formation of free sulphydryl groups during heating varied depending on heating time. A good linear correlation (r = 0.839) was found between brown coloured compounds and hydroxymethylfurfural content in milk samples during heating. Activation energies (Ea) for the formation of hydroxymethylfurfural and nonenzymatic brown coloured compounds were 96.31 and 69.79 kJ/mol, respectively. 相似文献
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J Walter A Capell AY Hung H Langen M Schn?lzer G Thinakaran SS Sisodia DJ Selkoe C Haass 《Canadian Metallurgical Quarterly》1997,272(3):1896-1903
The beta-amyloid precursor protein (betaAPP) is a transmembrane protein that is exclusively phosphorylated on serine residues within its ectodomain. To identify the cellular site of betaAPP phosphorylation, we took advantage of an antibody that specifically detects the free C terminus of beta-secretase-cleaved betaAPP containing the Swedish missense mutation (APPssw-beta). This antibody previously established the cellular location of the beta-secretase cleavage of Swedish betaAPP as a post-Golgi secretory compartment (Haass, C., Lemere, C., Capell, A., Citron, M., Seubert, P., Schenk, D., Lannfelt, L., and Selkoe, D. J. (1995) Nature Med. 1, 1291-1296). We have now localized the selective ectodomain phosphorylation of betaAPP to the same compartment. Moreover, the phosphorylation sites of betaAPP were identified at Ser198 and Ser206 of betaAPP695 by tryptic peptide mapping, mass spectrometry, and site-directed mutagenesis. Intracellular phosphorylation of betaAPP was inhibited by Brefeldin A and by incubating cells at 20 degrees C, thus excluding phosphorylation in the endoplasmic reticulum or trans-Golgi network. Ectodomain phosphorylation within a post-Golgi compartment occurred not only with mutant Swedish betaAPP, but also with wild type betaAPP. In addition to phosphorylation within a post-Golgi compartment, betaAPP was also found to undergo phosphorylation at the cell surface by an ectoprotein kinase. Therefore, this study revealed two distinct cellular locations for betaAPP phosphorylation. 相似文献