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31.
Fleischer RL Price PB Walker RM Filz RC Fukui K Friedlander MW Holeman E Rajan RS Tamhane AS 《Science (New York, N.Y.)》1967,155(3759):187-189
Cosmic ray nuclei have been observed with the use of plastic trackdetecting solids in satellites and high-altitude balloon flights. Nuclear emulsions in the stacks of plastic sheets allowed the positive identification of cosmic raynuclei as light as nitrogen. The most striking new information was the failure to observe relativistic iron nuclei, a result which has led to an advance in the understanding of track registration criteria. 相似文献
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34.
Induction of macrophage tumoricidal activity by granulocyte-macrophage colony-stimulating factor 总被引:38,自引:0,他引:38
K H Grabstein D L Urdal R J Tushinski D Y Mochizuki V L Price M A Cantrell S Gillis P J Conlon 《Science (New York, N.Y.)》1986,232(4749):506-508
Monocytes are a subpopulation of peripheral blood leukocytes, which when appropriately activated by the regulatory hormones of the immune system, are capable of becoming macrophages--potent effector cells for immune response to tumors and parasites. A complementary DNA for the T lymphocyte-derived lymphokine, granulocyte-macrophage colony-stimulating factor (GM-CSF), has been cloned, and recombinant GM-CSF protein has been expressed in yeast and purified to homogeneity. This purified human recombinant GM-CSF stimulated peripheral blood monocytes in vitro to become cytotoxic for the malignant melanoma cell line A375. Another T cell-derived lymphokine, gamma-interferon (IFN-gamma), also stimulated peripheral blood monocytes to become tumoricidal against this malignant cell line. When IFN-gamma activates monocytes to become tumoricidal, additional stimulation by exogenously added lipopolysaccharide is required. No such exogenous signals were required for the activation of monocytes by GM-CSF. 相似文献
35.
The brain in AIDS: central nervous system HIV-1 infection and AIDS dementia complex 总被引:90,自引:0,他引:90
R W Price B Brew J Sidtis M Rosenblum A C Scheck P Cleary 《Science (New York, N.Y.)》1988,239(4840):586-592
Infection with human immunodeficiency virus type 1 (HIV-1) is frequently complicated in its late stages by the AIDS dementia complex, a neurological syndrome characterized by abnormalities in cognition, motor performance, and behavior. This dementia is due partially or wholly to a direct effect of the virus on the brain rather than to opportunistic infection, but its pathogenesis is not well understood. Productive HIV-1 brain infection is detected only in a subset of patients and is confined largely or exclusively to macrophages, microglia, and derivative multinucleated cells that are formed by virus-induced cell fusion. Absence of cytolytic infection of neurons, oligodentrocytes, and astrocytes has focused attention on the possible role of indirect mechanisms of brain dysfunction related to either virus or cell-coded toxins. Delayed development of the AIDS dementia complex, despite both early exposure of the nervous system to HIV-1 and chronic leptomeningeal infection, indicates that although this virus is "neurotropic," it is relatively nonpathogenic for the brain in the absence of immunosuppression. Within the context of the permissive effect of immunosuppression, genetic changes in HIV-1 may underlie the neuropathological heterogeneity of the AIDS dementia complex and its relatively independent course in relation to the systemic manifestations of AIDS noted in some patients. 相似文献
36.
Conservation of brain amyloid proteins in aged mammals and humans with Alzheimer's disease 总被引:37,自引:0,他引:37
D J Selkoe D S Bell M B Podlisny D L Price L C Cork 《Science (New York, N.Y.)》1987,235(4791):873-877
The formation of clusters of altered axons and dendrites surrounding extracellular deposits of amyloid filaments (neuritic plaques) is a major feature of the human brain in both aging and Alzheimer's disease. A panel of antibodies against amyloid filaments and their constituent proteins from humans with Alzheimer's disease cross-reacted with neuritic plaque and cerebrovascular amyloid deposits in five other species of aged mammals, including monkey, orangutan, polar bear, and dog. Antibodies to a 28-amino acid peptide representing the partial protein sequence of the human amyloid filaments recognized the cortical and microvascular amyloid of all of the aged mammals examined. Plaque amyloid, plaque neurites, and neuronal cell bodies in the aged animals showed no reaction with antibodies to human paired helical filaments. Thus, with age, the amyloid proteins associated with progressive cortical degeneration in Alzheimer's disease are also deposited in the brains of other mammals. Aged primates can provide biochemically relevant models for principal features of Alzheimer's disease: cerebrovascular amyloidosis and neuritic plaque formation. 相似文献
37.
Radiation hybrid mapping: a somatic cell genetic method for constructing high-resolution maps of mammalian chromosomes 总被引:69,自引:0,他引:69
Radiation hybrid (RH) mapping, a somatic cell genetic technique, was developed as a general approach for constructing long-range maps of mammalian chromosomes. This statistical method depends on x-ray breakage of chromosomes to determine the distances between DNA markers, as well as their order on the chromosome. In addition, the method allows the relative likelihoods of alternative marker orders to be determined. The RH procedure was used to map 14 DNA probes from a region of human chromosome 21 spanning 20 megabase pairs. The map was confirmed by pulsed-field gel electrophoretic analysis. The results demonstrate the effectiveness of RH mapping for constructing high-resolution, contiguous maps of mammalian chromosomes. 相似文献
38.
Using refractometry and ultraviolet-difference spectroscopy to indicate interaction between proteins and coinpounds of low molecular weight, we found a protein fraction in bovine tongue extracts that coinplexes sugars and saccharin. The strengths of the coinzplexes parallel the degrees of sweetness of the compounds, and the effects of pH upon formation of complexes parallel the effects of pH upon sensitivity of taste buds to sweet compounds in vivo. 相似文献
39.
Fleischer RL Haines EL Hanneman RE Hart HR Kasper JS Lifshin E Woods RT Price PB 《Science (New York, N.Y.)》1970,167(3918):568-571
Particle tracks in Apollo 11 samples are dominantly of cosmic ray and solar origin: primary galactic and solar flare particles, likely spallation recoil tracks, and possible solar-wind heavy particles. The energy spectrum of irongroup nuclei is inferred from track density gradients in surface layers, and a limit of < 10(-7) centimeter per year is deduced for the surface erosion rate. From cosmic ray tracks in rock and core samples it is clear that the lunar soil is stirred often during each few million years. X-rays reveal augite, anorthite, olivine, ilmenite, troilite, nonmeteoritic iron, and assorted glasses, but no major structural damage. Hydrogen, helium, and other gases in the fines are compatible with expected solar wind ratios. 相似文献
40.
Bladder tumors in rats fed cyclohexylamine or high doses of a mixture of cyclamate and saccharin 总被引:8,自引:0,他引:8
J M Price C G Biava B L Oser E E Vogin J Steinfeld H L Ley 《Science (New York, N.Y.)》1970,167(921):1131-1132
Papillary transitional cell tumors were found in the urinary bladders in 8 rats out of 80 that received 2600 milligrams per kilogram of body weight per day of a mixture of sodium cyclamate and sodium saccharin (10:1) for up to 105 weeks. From week 79 on, several of these rats received cyclohexylamine hydrochloride (125 milligrams per kilogram per day, the molecular equivalent of the conversion of about 10 percent of the cyclamate dosage to cyclohexylamine) in addition to the sodium cyclamate and sodium saccharin. In another study in which 50 rats were fed daily 15 milligrams of cyclohexylamine sulfate per kilogram of body weight for 2 years, eight males and nine females survived. One of the eight males had a tumor of the urinary bladder. In neither study were bladder tumors found in the control rats or in rats treated with lower doses of the compounds. 相似文献