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91.
Electrical properties of gap junction channels in guinea-pig ventricular cell pairs revealed by exposure to heptanol 总被引:1,自引:0,他引:1
Cell pairs were isolated from adult guinea pig ventricles to study the electrical properties of gap junction channels. The experiments involved a double voltage-clamp approach and whole-cell, tight-seal recording. Heptanol decreased the intracellular current, In, in a dose-dependent fashion. Before complete uncoupling, In showed fluctuations suggesting the operation of gated channels. In the presence of 3 mM heptanol, In showed quantal steps arising from spontaneous opening and closing of single channels. The IV-relationship of the channels was linear (range: +/- 95 mV). Analysis of current records revealed the following single-channel conductances, gamma n: Mean value = 37 pS; median value = 33 pS. gamma n was insensitive to the non-junctional membrane potential (range: -90 to +10 mV). 3 mM ATP4- in the pipette solution had no effects on gamma n, 6 mM ATP4- produced a small decrease, and 6 mM ATP + 0.1 mM cAMP- an increase in gamma n. Channel transitions from closed to open state were variable (range of apparent time constants: 2.5-32 ms; mean: 11 ms). 相似文献
92.
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94.
Ian A. Maxwell Edwin M. F. J. Verdurmen Anton L. German 《Macromolecular chemistry and physics.》1992,193(10):2677-2695
The four important factors that determine the rate of emulsion polymerization are the propagation rate coefficient, the latex-particle concentration, the monomer concentration in the latex particles, and the free-radical concentration in the latex particles. Both theoretical considerations and experimental evidence suggest that the important factors that may reduce the rate of emulsion polymerization at high conversion are the propagation rate coefficient and the monomer concentration in the latex particles, and not the free-radical concentration in the latex particle, if the initiator is not depleted. Various approaches for increasing the rate of emulsion polymerization at high conversion are suggested. 相似文献
95.
Ghiorzo P Villaggio B Sementa AR Hansson J Platz A Nicoló G Spina B Canepa M Palmer JM Hayward NK Bianchi-Scarrà G 《Human pathology》2004,35(1):25-33
Little is known about the correlation between the loss of p16 expression and tumor progression in familial melanoma; no systematic study has been conducted on p16 expression in melanocytic tumors from patients carrying germline CDKN2A mutations. We analyzed 98 early primary lesions from familial patients, previously tested for germline CDKN2A status, by quantitative immunohistochemistry using 3 p16 antibodies. We found that p16 expression was inversely correlated with tumor progression and was significantly lower in melanomas, including in situ lesions, than in nevi. Of other features analyzed, tumor thickness showed the most significant correlation with p16 levels. Lesions from mutation-negative patients displayed combined nuclear and cytoplasmic staining. However, some mutation-positive lesions (ie, G101W, 113insR, M53I, R24P, and 33ins24), including benign nevi, showed nuclear mislocalization, confirming previous studies suggesting that subcellular distribution indicates functional impairment of p16. 相似文献
96.
97.
Sainova IV Kril AI Simeonov KB Popova TP Ivanov IG 《Journal of virological methods》2005,124(1-2):37-40
The ability for replication of vaccine avian pox viral strains FK and Dessau in cell clones, derived from the EBTr cell line, derived from embryonic bovine trachea, was studied. The derived seven cell clones showed different morphological characteristics and diverse sensitivity to both vaccine avian pox viral strains. Hence, the EBTr-derived cell clones could be used for cultivation, as well as for differentiation of vaccine avian pox viral strains. In addition, studies have been undertaken to elucidate the possible use of cultivated strains in these heterologous cell culture system's vaccine avian pox viral strains for biotechnology, as well as for solving problems, related to infection of people with avian viruses. 相似文献
98.
The deprivation effect (DE)--an increase in the level of free-choice consumption of alcohol after a period of forced abstinence--may reflect relapselike drinking and be relevant for modeling alcohol abuse. However, the behavioral mechanisms of the DE are unclear. In these experiments, rats had unlimited free-choice access to water and saccharin-containing solutions and underwent repeated episodes of saccharin deprivation. It was found that DE magnitude correlates positively with the deprivation phase duration, expression of the DE is highly context dependent, and the DE can be prevented by extinguishing response to the saccharin-associated stimuli. Thus, DE procedures may be useful for studying the effects of continued exposure to stimuli associated with various primary reinforcers such as drugs of abuse. 相似文献
99.
The expression of CD45R on mouse T cells has been studied. This antigen is expressed on the two higher molecular weight bands of CD45 (or T200) and in mouse it is currently used as a marker of B cells (B220). Here we confirm that CD45R is expressed on some mouse T cell clones. We show that a small but measurable proportion of mouse spleen and peripheral blood lymphocyte T cells gives positive immunofluorescence with B220. Also CD45R-specific antibodies increase the proliferation response to phytohemagglutinin up to 3-fold, thus confirming that CD45R molecules transduce a signal into mouse T cells. 相似文献
100.
Riedl M Czech T Slootweg J Czernin S Hainfellner JA Schima W Vierhapper H Luger A 《Endocrine pathology》1995,6(2):159-166
This report describes a case of lymphocytic hypophysitis in a 63-year-old man who presented with symptoms of a pituitary mass
lesion associated with hypothyroidism and hypogonadism. Postoperative endocrinological testing demonstrated gonadotropic,
thyrotropic, and corticotropic hypopituitarism, and the patient was commenced on replacement therapy with hydrocortisone and
levothyroxine. Histological examination of the pituitary tissue obtained by transsphenoidal surgery revealed lymphocytic hypophysitis
without evidence of a pituitary adenoma. The vast majority of patients with lymphocytic hypophysitis are women particularly
during pregnancy and the puerperium. Until recently only four men were reported in the literature. The pathogenesis of lymphocytic
hypophysitis is uncertain but autoimmune mechanisms are possibly involved. 相似文献