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Objective: To provide extended intra-oral delivery of a saliva substitute. Intervention: Three different types of prostheses containing saliva substitute were designed and assessed: a two-part device resembling a mandibular complete denture sealed by cobalt-samerium magnets, a one-part clear resin device for the edentate patients and a flexible mouth guard type of appliance containing a lubricant releasing bubble for the dentate patients. Setting: A teaching hospital Oral Medicine and Rheumatology Clinic. Subjects: 8 edentate and 3 dentate Sjogren Syndrome sufferers. Outcome measures: Subjective dryness after a week of wearing the lubricating appliance. Results: The majority of the subjects wore the appliances for 6–12 hours during each 24 hours. The initial dryness severity diminished after wearing the lubricating prosthesis. The patients preferred to wear the appliance at night. Conclusion: All criteria were fulfilled on designing a saliva substitute lubricating appliance and some of the subjects have worn this prosthesis successfully for up to 3 years. Particular benefit was obtained by night-time wear. 相似文献
875.
Evolutionary approaches in human cognitive neurobiology traditionally emphasize macroscopic structures. It may soon be possible
to supplement these studies with models of human information-processing of the molecular level. Thin-film, simulation, fluorescence
microscopy, and high-resolution X-ray crystallographic studies provide evidence for transiently organized neural membrane
molecular systems with possible computational properties. This review article examines evidence for hydrophobic-mismatch molecular
interactions within phospholipid microdomains of a neural membrane bilayer. It is proposed that these interactions are a massively
parallel algorithm which can rapidly compute near-optimal solutions to complex cognitive and physiological problems. Coupling
of microdomain activity to permenant ion movements at ligand-gated and voltage-gated channels permits the conversion of molecular
computations into neuron frequency codes. Evidence for microdomain transport of proteins to specific locations within the
bilayer suggests that neuromolecular computation may be under some genetic control and thus modifiable by natural selection.
A possible experimental approach for examining evolutionary changes in neuromolecular computation is briefly discussed.
Received: 2 October 1998 / Accepted in revised form: 19 March 1999 相似文献
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Ligand-dependent regulation of the 1,25-dihydroxyvitamin D3 receptor in rat osteosarcoma cells 总被引:1,自引:0,他引:1
The specific binding of radiolabeled 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) to intact rat osteosarcoma (ROS 17/2) cells was followed for 24 h. In the presence of 0.5-1.5 nM 1,25(OH)2D3, hormone binding increased over a period of 12 h, from 1.1 X 10(4) to 1.3 X 10(5) receptors/cell. The elevated level of hormone binding persisted through 24 h provided that the initial concentration of hormone was maintained. The concentration dependence of this increase in receptor level was centered between 10 and 30 pM 1,25(OH)2D3, and the binding at 12 h exhibited the metabolite specificity expected for a 1,25(OH)2D3 receptor. The t 1/2 values for the disappearance of unoccupied and occupied receptors were roughly the same, approximately 2.7 h; therefore, the increase in hormone binding was not due to receptor stabilization. In comparison, hormone-receptor complexes appeared to dissociate with a t 1/2 of 1 h. alpha-Amanitin treatment reduced the magnitude of receptor accumulation by 50-60%, indicating that mRNA synthesis was required to achieve the maximal response. Ligand-dependent regulation of cellular receptor levels provides a mechanism for amplifying the primary hormonal signal and is predicted to influence the kinetics, magnitude, and dose dependence of cellular responses. 相似文献
878.
A Price 《FEBS letters》1992,300(1):101-104
The 5'----3' exonuclease activity of E. coli DNA polymerase I and a related enzyme activity in mammalian cell nuclei, DNase IV, are unable to catalyse the excision of free deoxyribose-phosphate from apurinic/apyrimidinic (AP) sites incised by an AP endonuclease. Instead, the sugar phosphate residue is slowly released as part of a short oligonucleotide. These products have been characterised as dimers and trimers by comparison of their retention time on reverse-phase HPLC with reference compounds prepared by acid depurination of a dinucleotide, trinucleotide and tetranucleotide containing a 5'-terminal dAMP residue. The similar mode of action of these enzymes at 5'-incised AP sites provides an explanation for the minority of repair patches larger than one nucleotide observed when AP sites are repaired by E. coli and mammalian cell extracts in vitro and strengthens the functional analogy between the two activities. 相似文献
879.
Gene transfer of H-2 class II genes: antigen presentation by mouse fibroblast and hamster B-cell lines 总被引:13,自引:0,他引:13
B Malissen M P Price J M Goverman M McMillan J White J Kappler P Marrack A Pierres M Pierres L Hood 《Cell》1984,36(2):319-327
We have transferred the mouse Ak alpha and Ak beta genes, which encode the class II I-Ak molecule, into mouse L-cell fibroblasts and hamster B cells. I-Ak molecules are expressed on the surface of both cell types. The L-cell and hamster B-cell I-Ak molecules appear normal by serological analyses and two-dimensional gel electrophoresis. Furthermore, the I-Ak molecules on L cells can act as targets for the allogenic T-cell killing of the transformed L cells. The I-Ak molecules in both mouse fibroblasts and hamster B cells can present certain antigens to T-cell helper hybridomas. Thus only class II molecules are required to convert the nonantigen-presenting cell. Accordingly, it will be possible to dissect the structure-function relationships existing between Ia molecules, foreign antigen, and T-cell receptor molecules by in vitro site-directed mutagenesis and gene transfer. 相似文献
880.
K Fujimoto D N Granger L R Johnson V H Price T Sakata P Tso 《Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N.Y.)》1992,200(3):409-413
The aim of this study was to determine whether the circadian changes in ornithine decarboxylase (ODC) activity of different segments of the small intestine were governed by factors other than food intake. First, the effects of fasting on mucosal ODC activity were examined. The results indicate that mucosal ODC activity in 24 hr and 48 hr fasted rats decreased significantly compared with ad libitum-fed rats. Second, the circadian rhythm of mucosal ODC activity was characterized by measuring mucosal ODC activity in fasted rats at four time points (09:00, 15:00, 21:00, and 03:00 hr; light period: 06:00-18:00 hr). The results from this study indicate that there is a detectable baseline ODC activity in different segments of fasting intestine. In duodenum, mucosal ODC activity was highest at 15:00 hr (light period), a time at which the rat was normally not eating. In jejunum and ileum, mucosal ODC activity increased between 21:00 and 03:00 hr (dark period). The observation that small intestine exhibits a distinct circadian rhythm of ODC activity in fasted rats suggests that not only food but also intrinsic factors can modulate physiologic oscillations in mucosal ODC activity. 相似文献