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51.
Protein polymorphism as a phase of molecular evolution 总被引:48,自引:0,他引:48
52.
Mailman MD Feolo M Jin Y Kimura M Tryka K Bagoutdinov R Hao L Kiang A Paschall J Phan L Popova N Pretel S Ziyabari L Lee M Shao Y Wang ZY Sirotkin K Ward M Kholodov M Zbicz K Beck J Kimelman M Shevelev S Preuss D Yaschenko E Graeff A Ostell J Sherry ST 《Nature genetics》2007,39(10):1181-1186
The National Center for Biotechnology Information has created the dbGaP public repository for individual-level phenotype, exposure, genotype and sequence data and the associations between them. dbGaP assigns stable, unique identifiers to studies and subsets of information from those studies, including documents, individual phenotypic variables, tables of trait data, sets of genotype data, computed phenotype-genotype associations, and groups of study subjects who have given similar consents for use of their data. 相似文献
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Summary A quick method for measuring the expansibility of erythrocytes during the course of hypotonic hemolysis has been developed, using the MCV continuous analyzer. By this method not only the volume changes during hypotonic hemolysis, but also the critical volume, at which hemolysis of the cells occurs, could be measured in a few minutes. Furthermore, data are presented demonstrating the following; when the MCV or the MCH was larger, the critical volume increased, but the expansion ratio (critical volume/initial volume) was almost constant, about 1.90, for most erythrocytes. 相似文献
55.
Dysplasia of subcommissural organ in congenital hydrocephalus spontaneously occurring in CWS/Idr rats 总被引:1,自引:0,他引:1
The subcommissural organ (SCO) of the congenital hydrocephalus spontaneously occurring in CWS/Idr rats was severely reduced in size and displaced at some distance from the anterior end of the cerebral aqueduct. The cerebral aqueduct of the hydrocephalic rats was open throughout its total length during postnatal days 1-20, though it was somewhat narrower at its middle region than in the normal brain. 相似文献
56.
Na-Ca exchange current in mammalian heart cells 总被引:27,自引:0,他引:27
Electrogenic Na-Ca exchange has been known to act in the cardiac sarcolemma as a major mechanism for extruding Ca ions. Ionic flux measurements in cardiac vesicles have recently suggested that the exchange ratio is probably 3 Na:1 Ca, although a membrane current generated by such a process has not been isolated. Using the intracellular perfusion technique combined with the whole-cell voltage clamp, we were able to load Na+ inside and Ca2+ outside the single ventricular cells of the guinea pig and have succeeded in recording an outward Na-Ca exchange current while blocking most other membrane currents. The current is voltage-dependent, blocked by La3+ and does not develop in the absence of intracellular free Ca2+. This report presents the first direct measurement of the cardiac Na-Ca exchange current, and should facilitate the study of Ca2+ fluxes during cardiac activity, together with various electrical changes attributable to the Na-Ca exchange and the testing of proposed models. 相似文献
57.
Genetic linkage of vitelliform macular degeneration (Best's disease) to chromosome 11q13. 总被引:9,自引:0,他引:9
Macular degeneration is the most common cause of legal blindness in older patients in developed countries. Best's vitelliform dystrophy is an early-onset, autosomal dominant form of macular degeneration characterized by an egg-yolk-like collection of lipofuscin beneath the pigment epithelium of the retinal macula. Fifty-seven members of a five-generation family affected with this disease were studied. A combination of ophthalmoscopy and electro-oculography was used for diagnosis; 29 patients were found to be affected and 16 unaffected. Linkage analysis mapped the disease-causing gene to chromosome 11q13. Three markers in this region were found to be significantly linked (Zmax > 3.0) to the disease. Multipoint analysis yielded a maximum Lod score of 9.3 in the interval between markers INT2 and D11S871. 相似文献
58.
Voltage dependence of Na/K pump current in isolated heart cells 总被引:8,自引:0,他引:8
The Na/K pump usually pumps more Na+ out of the cell than K+ in, and so generates an outward component of membrane current which, in the heart, can be an important modulator of the frequency and shape of the cardiac impulse. Because it is electrogenic, Na/K pump activity ought to be sensitive to membrane potential, and it should decline with hyperpolarization. However, such voltage dependence of outward pump current has yet to be demonstrated, one reason being the technical difficulty of accurately measuring pump current over a sufficiently wide voltage range. The whole-cell patch-clamp technique allows effective control of both intracellular and extracellular solutions as well as membrane voltage. Applying this technique to myocardial cells isolated from guinea pig ventricle, we have measured Na/K pump current between -140 mV and +60 mV, after minimizing passive currents flowing through Ca2+, K+ and Na+ channels. We report here that strongly activated pump current shows marked voltage dependence; it declines steadily from a maximal level near 0 mV, becoming very small at -140 mV. Pump current-voltage relationships will provide essential information for testing models of the Na/K pump mechanism and for predicting pump-mediated changes in the electrical activity of excitable cells. 相似文献
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Lee S Pirogov A Kang M Jang KH Yonemura M Kamiyama T Cheong SW Gozzo F Shin N Kimura H Noda Y Park JG 《Nature》2008,451(7180):805-808
The motion of atoms in a solid always responds to cooling or heating in a way that is consistent with the symmetry of the given space group of the solid to which they belong. When the atoms move, the electronic structure of the solid changes, leading to different physical properties. Therefore, the determination of where atoms are and what atoms do is a cornerstone of modern solid-state physics. However, experimental observations of atomic displacements measured as a function of temperature are very rare, because those displacements are, in almost all cases, exceedingly small. Here we show, using a combination of diffraction techniques, that the hexagonal manganites RMnO3 (where R is a rare-earth element) undergo an isostructural transition with exceptionally large atomic displacements: two orders of magnitude larger than those seen in any other magnetic material, resulting in an unusually strong magneto-elastic coupling. We follow the exact atomic displacements of all the atoms in the unit cell as a function of temperature and find consistency with theoretical predictions based on group theories. We argue that this gigantic magneto-elastic coupling in RMnO3 holds the key to the recently observed magneto-electric phenomenon in this intriguing class of materials. 相似文献