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981.
An optical fiber probe is used to both excite and collect fluorescence from a suspension of cells. The configuration of the probe is such that one or a few cells are sensed at a time, with a convenient cell concentration. With fluorescently labeled antibodies to cellular antigens, the fiber optic cytometer is able to identify the presence of a specific set of cells with high sensitivity. 相似文献
982.
Characterization of hemolytic bacteria in subgingival plaque 总被引:3,自引:0,他引:3
J. D. Hillman M. F. J. Maiden S. P. Pfaller L. Martin M. J. Duncan S. S. Socransky 《Journal of periodontal research》1993,28(3):173-180
Three-quarters of the patients with periodontal diseases surveyed in this study had one or more distinct types of hemolytic bacteria in their subgingival plaque. Twelve different species of bacteria were identified, belonging to five genera (Actinomyces, Streptococcus, Staphylococcus, Prevotella, and Actinobacillus). Nine hemolytic isolates, consisting of four Prevotella denticola strains, two Actinomyces naeslundii genospecies 2 strains, and one each of P. melaninogenica, Streptococcus constellatus, and A. naeslundii genospecies 1 strains were characterized. Incorporation of pronase into blood agar medium inhibited hemolysis by all of the isolates, suggesting a proteinaceous component for each of their hemolysins. With one exception, hemolysin production appeared to be regulated by the concentration of environmental iron: exogenous hemin was found to inhibit hemolysin production, and the iron scavenging compound, 2,2′-dipyridyl, was found to promote hemolysin production by all of the strains except for the S. constellatus isolate. Genomic libraries of each of the hemolytic plaque isolates were prepared in Escherichia coli using pBR322. Hemolytic clones were isolated on blood agar medium containing ampicillin at frequencies ranging from 1–6.7 × 10?4. Extensive restriction mapping revealed regions of homology in the case of clones derived from three P. denticola strains isolated from the same subject. Two of the P. denticola-derived clones were virtually identical throughout the entirety of their > 5 Kb inserts. The clone derived from the third strain showed good homology to the other two within a 1.3 Kb region, but the flanking DNA showed no homology even though all three P. denticola isolates were shown to be clonally related by ribotyping. The results indicate that hemolytic bacteria are frequently recovered from active disease sites of subjects with periodontal diseases. The hemolytic phenotype appears to be restricted to a small proportion of the total number of species normally resident in subgingival plaque. Restriction mapping suggested that a variety of hemolysin genes may be involved and that, at least in certain cases, they may be on mobile genetic elements. 相似文献
983.
984.
985.
本文讨论了基于直接最小二乘辩识方法的两输入两输出闭环系统的可辩识性条件,对人控两输入两输出补偿跟踪系统的实验及参数估计方法进行了讨论,同时给出参数估计的广义最小二乘算法公式。 相似文献
986.
T H Huisman 《American journal of hematology》1979,6(2):173-184
Sickle cell (SS) disease is a complex of various genetic conditions. In some, homozygosity for the beta S gene may be present alone or in combination with the heterozygous or homozygous alpha-thalassemia-2 condition. Such combinations might ameliorate the clinical and hematological condition of the patient. The same may be true for the high levels of Hb F and F-cells observed in many Hb S homozygotes. Howeever, the chemical heterogeneity of Hb F appears not to be related to the clinical status of the Hb S homozygote. Combinations of a Hb S heterozygosity with a heterozygosity for a Hb D-type of variant, for either one of two types of beta-thalassemia, two types of alpha beta- thalassemia, and five types of HPFH are discussed, and data are compared with those obtained for Hb S homozygotes. The use of advanced laboratory procedures and family studies is often necessary for an accurate diagnosis. 相似文献
987.
Henry I. Yamamura Thomas W. Vickroy Donald R. Gehlert James K. Wamsley William R. Roeske 《Brain research》1985,325(1-2)
(+)-cis-[3H]Methyldioxolane ((+)-[3H]CD), a potent muscarinic agonist, was used to label high-affinity agonist states of muscarinic receptors in thin tissue sections of the rat central nervous system. Light microscopic autoradiography of atropine-sensitive (+)-[3H]CD binding sites revealed regions of dense labeling (superior colliculus, inferior colliculus, lateral geniculate body, hypoglossal (XII) nucleus, facial (VII) nucleus, tractus diagonalis) and regions of sparse labeling (hippocampus, dentate gyrus). The inverse regional correlation between high-affinity (+)-[3H]CD states and binding sites for the muscarinic antagonists [3H]pirenzepine (r = −0.79) and (-)-[3H]quinuclidinyl benzilate (r = −0.30) underscores potentially important differences between agonist and antagonist binding to CNS tissue slices. 相似文献
988.
Robert I Kelly 《The Australasian journal of dermatology》1995,36(3):109-119
Cutaneous involvement may occur with virtually all syndromes of vasculitis. This can occur primarily as a dermatologic disorder or as a manifestation of a potentially life threatening systemic vasculitis. In this review article, classification, clinical manifestations, pathogenesis and therapy of cutaneous vasculitis will be discussed. Disorders which are primarily vascular in origin but lack a well defined inflammatory phase, referred to as ‘vasculopathies’ will also be discussed. 相似文献
989.
990.
R. Bonnichsen C. G. Fri R. Hjälm J. Petrovics R. Ryhage 《International journal of legal medicine》1973,71(4):270-273
Summary Gas chromatography in combination with high and low resolution mass spectrometry has been used for identification of metabolites of dextropropoxyphene isolated from liver extract.
Zusammenfassung Für die Identifikation der Metaboliten von Dextropropoxyphen aus Leberextrakten wurde eine Kombination der Gaschromatographie mit der hoch und niedrig auflösenden Massenspektrometrie angewandt.相似文献