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61.
K T Wheeler G B Nelson K E Terrell C A Wallen 《International journal of radiation biology》1988,54(2):245-255
The radiosensitivity and kinetics of repair of radiation-induced DNA damage were determined for proliferative (P) and quiescent (Q) cells of the mouse mammary adenocarcinoma line 67. 67 Q cells are more radiosensitive than 67 P cells. Radiation induced the same amount of DNA damage in both 67 P and 67 Q cells. Both 67 P and 67 Q cells repaired their DNA damage with biphasic kinetics, but the half-times for the fast and slow phase were longer in 67 Q cells. Q cell DNA appeared to be in a more compact or condensed chromatin structure and was less accessible to enzymatic digestion than P cell DNA. These data suggest that 67 Q cells are more sensitive to ionizing radiation than 67 P cells because they repair their radiation-induced DNA damage more slowly, perhaps as a result of their more condensed chromatin structure. 相似文献
62.
Human myeloid alpha 3-fucosyltransferase is involved in the expression of the sialyl-Lewis(x) determinant, a ligand for E- and P-selectin 总被引:1,自引:0,他引:1
Easton EW; Schiphorst WE; van Drunen E; van der Schoot CE; van den Eijnden DH 《Blood》1993,81(11):2978-2986
The sialyl-Lex determinant (NeuAc alpha 2-->3Gal beta 1-->4[Fuc alpha- 1-->3]GlcNAc) has been identified as a major ligand in the selectin- mediated adhesion of neutrophils and monocytes to activated endothelium or platelets. This carbohydrate epitope is formed by the sequential action of alpha 3-sialyltransferase and alpha 3-fucosyltransferase on N- acetyllactosamine (Gal beta 1-->4GlcNAc) disaccharide termini of glycoconjugates. We have addressed the role of the human myeloid alpha 3-fucosyltransferase in the expression of this epitope at the leucocyte surface by determining its activity in human-mouse leukemic cell hybrids (WEGLI), normal human granulocytes and chronic myeloid leukemia (CML) cells using sialylated and desialylated glycoproteins and oligosaccharides as acceptor substrates. In contrast to what has been reported for the myeloid-type enzyme, we found that the alpha 3- fucosyltransferase of the cells studied can use sialylated acceptors be it that the activity is several times lower than with asialo- substrates. Characterization of the product obtained with a sialylated oligosaccharide indicated that the enzyme can catalyze the formation of the sialyl-Le(x) structure. Flow cytometry of the WEGLI cells using a sialyl-Le(x)-specific monoclonal antibody (MoAb) showed that these cells indeed express sialyl-Lex at their surface, provided that they contain human chromosome 11. Earlier the presence of this chromosome had been correlated with the expression of alpha 3-fucosyltransferase activity. In addition to sialyl-Le(x), WEGLI cells containing chromosome 11 showed high-expression levels of related structures recognized by antibodies VIM-2 and VIM-8, suggesting that fucose addition can occur at both distal and proximal GlcNAc residues in poly- N-acetyl-lactosaminoglycan sequences. Based on the human chromosome contents it could be ruled out that the alpha 3-fucosyltransferase of WEGLI cells is a Lewis-type alpha 3/4- or plasma-type alpha 3- fucosyltransferase, the genes of which have been mapped to chromosome 19. It is concluded that the enzyme studied is of the myeloid-type and indeed is involved in the synthesis of sialyl-Le(x) (and also VIM-2 and VIM-8 structures) in leukocytes provided that its expression is at a sufficiently high level. 相似文献
63.
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65.
On the Theory of Ion Transport Across the Nerve Membrane, III. Potassium Ion Kinetics and Cooperativity (with x = 4, 6, 9) 总被引:1,自引:0,他引:1
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Terrell L. Hill Yi-Der Chen 《Proceedings of the National Academy of Sciences of the United States of America》1971,68(10):2488-2492
The calculations of Part II of this series have been extended to square (x = 4) and octahedral (x = 6) arrangements of subunits in a potassium channel (or gate). The conclusion is the same as before: experimental induction and superposition properties of gK(t), on depolarization, seem to rule out any significant degree of interaction or cooperativity between the (protein?) subunits of K+ channel. Calculations for x = 4, 6, and 9 have also been made for a square lattice of interacting channels (periodic boundary conditions). Because of apparent rapid convergence with x, it seems fairly safe to conclude that this model is unsatisfactory. There is some difficulty with superposition but the principal shortcoming is a failure to produce induction behavior. Aggregation models for the K+ channel are also discussed briefly here. They, too, appear rather unpromising (for the same reasons as seem to exclude conformational cooperativity within a channel). 相似文献
66.
Some characteristics of an exceptionally potent inhaled anesthetic: thiomethoxyflurane 总被引:1,自引:0,他引:1
The authors sought to test whether a deviation existed for the correlation between anesthetic potency and the oil/gas partition coefficient at an extreme of lipid solubility. For thiomethoxyflurane, the sulfur analog of methoxyflurane, the oil/gas partition coefficient was 7230 +/- 50 SEM, and MAC (minimum alveolar concentration of thiomethoxyflurane required for anesthesia) in 4 dogs was 0.035 +/- 0.008 percent of 1 atm. This agrees with the potency predicted by the lipid solubility, although thiomethoxyflurane is 7 1/2 times more potent than methoxyflurane, to date the most potent available anesthetic. Thiomethoxyflurane water/gas and blood/gas partition coefficients were 5.4 +/- 0.3 and 68.1 +/- 1.5, respectively. The latter coefficient accords with the prolonged recovery associated with this agent. Renal and hepatic blood chemistries measured on the 1st and 7th days following anesthesia showed only small changes from preanesthetic values. 相似文献
67.
A single, 10 ng intradermal injection of human recombinant interleukin-1 (rIL-1) into rat ears produced acute inflammation. Tissue wet weight (edema) and total myeloperoxidase activity (PMN accumulation), peaked at 3 hours and returned to base line at 3 days. Given orally, 1 hour prior to rIL-1 injection, cyproheptadine, dexamethasone, conventional NSAID's, or mixed cyclooxygenase/lipoxygenase inhibitors were potent antagonists of edema and moderate antagonists of PMN accumulation. In addition, the putative DMARD's, auranofin, dapsone, and levamisole were effective inhibitors of rIL-1 induced inflammation. 相似文献
68.
LeRoy AJ; Williams HJ Jr; Bender CE; Segura JW; Patterson DE; Benson RC 《Radiology》1985,155(1):83-85
Two patients had colonic perforation as a result of percutaneous nephrostomy placement followed by track dilatation and renal calculus removal. We present the technical aspects of nephrostomy placement and stone removal, as well as the clinical diagnosis and management of these cases. Both patients recovered well with conservative therapy and required no surgical intervention. This report reviews the anatomic considerations for percutaneous nephrostomy in patients undergoing renal stone removal. 相似文献
69.
Taylor JC Terrell JE Ronis DL Fowler KE Bishop C Lambert MT Myers LL Duffy SA Bradford CR Chepeha DB Hogikyan ND Prince ME Teknos TN Wolf GT;University of Michigan Head Neck Cancer Team 《Archives of otolaryngology--head & neck surgery》2004,130(6):764-769
BACKGROUND: Patients with head and neck cancer often experience debilitating speech, eating, and respiratory problems as well as the psychological effects of loss of function and change in body image. These patients often become unemployed as a result of their disease process, which adds financial burden to their already stressful lives. Yet the specific factors associated with unemployment have not been systematically studied. METHODS: This multisite study used survey and chart data to determine the predictors of work-related disability. RESULTS: Of the 384 patients who were working prior to their diagnosis of head and neck cancer, 52% (n = 201) were disabled by their cancer treatment. Multivariate analysis demonstrated significant links between disability and chemotherapy (odds ratio [OR], 3.4; P <.001), neck dissection status (OR, 2.3; P =.01), pain scores (OR, 1.2; P =.01), and time since diagnosis (OR, 0.9; P =.04). CONCLUSIONS: More than half of the patients in this study were disabled by their head and neck cancer or treatment. Patients with head and neck cancer who have undergone chemotherapy or neck dissection or have high pain scores are at increased risk for disability from their cancer or their treatment. Efforts to prevent (if possible), better assess, and treat pain and other adverse effects of head and neck cancer treatments may also have the potential to reduce patient disability. 相似文献
70.
Trigeminal trophic syndrome (TTS) is an unusual complication after peripheral or central damage to the trigeminal nerve, characterized by anesthesia, paresthesias, and ala nasi ulceration. We describe a patient with classic TTS after trigeminal rhizotomy who underwent several extensive evaluations for nasal ulceration and received prolonged immunosuppressive therapy for a presumed autoimmune disorder before the correct diagnosis was made. An understanding of the predisposing factors and clinical presentation of TTS is important to ensure a timely diagnosis of this difficult-to-treat illness. Differentiation of TTS from malignancy, infection, or vasculitis is possible on the basis of clinical history, tissue biopsy, and serologic evaluation. 相似文献