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1.
Difficulties were encountered with the orcein method currently being used to demonstrate hepatitis B surface antigen and copper-associated protein in the liver when a new batch of dye was introduced. A survey of published material produced a plethora of methods with many contradictory recommendations. A number of methods and a variety of orceins were compared to determine which methods and orcein solutions would give the most consistent results. Two methods gave equally satisfactory results and can be recommended for routine use in screening paraffin sections of liver for hepatitis B surface antigen and copper-associated protein. 相似文献
2.
Abstract. Cell aggregation in Dictyostelium discoideum is a chemotactic process mediated by cyclic adenosine monophosphate (CAMP), which is detected by cell surface receptors. The cAMP signal is degraded by cAMP phosphodiesterase. The possibility that cAMP signals are also used for cell communication in the multicellular stages was studied by determining whether the cAMP receptors, which are essential for signal transduction, continue to function in these stages. During slug migration, the number of binding sites per cell decreases to about 15% of the maximum level acquired during aggregation. At the onset of fruiting body formation, a three- to Four-Fold increase in cAMP binding activity occurs. This increase coincides with an increase in cAMP phosphodiesterase. Both phenomena suggest that cell-cell communication mediated by cAMP is used during culmination. During both slug migration and early culmination, the prestalk cells exhibit about twice as much binding activity as the prespore cells. 相似文献
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To date, the effects of long-term growth hormone (GH)-releasing hormone [GHRH(1-29)-NH2] treatment on the plasma concentrations of somatostatin-like immunoreactivity (SLI) remain undefined. In the present study, the effect of GHRH(1-29)-NH2 therapy on plasma SLI levels has been studied in 11 non-GH-deficient children. The pattern of administration was 5 micrograms/kg body weight, given subcutaneously once every day. There was no significant change in plasma SLI levels after bolus injection of GHRH(1-29)-NH2 before and during GHRH(1-29)-NH2 therapy. However, plasma SLI rose in basal plasma and nocturnal sleep after 3 months of GHRH(1-29)-NH2 therapy and remained the same during 6 months of treatment with GHRH(1-29)-NH2. The reason for this finding is uncertain, but an increase in SLI release from the enteroinsular axis is a possible explanation. The association of our findings with the role of the circulating SLI on nutrient homeostasis and the effects of GNRH on growth velocity is discussed. 相似文献
5.
PYCNOGENOL is an antioxidant phytochemical shown to have antiinflammatory activity in both the in vitro and in vivo models. This study compared the effects of chewing gums with and without PYCNOGENOL on gingival bleeding and plaque formation in 40 human subjects. In this double-blind study, subjects were assigned randomly to receive either control gums without PYCNOGENOL or experimental gums containng 5 mg PYCNOGENOL. Subjects used chewing gums for 14 days. Gingival bleeding and plaque scores were taken before and after the experiment. PYCNOGENOL chewing gums significantly reduced gingival bleeding, while no changes were noted in bleeding indexes in control subjects who used regular chewing gums. Subjects using regular control gums had significant increases of dental plaque accumulation during the two-week period. No increases in plaque accumulation were noted in subjects using PYCNOGENOL chewing gums. The data of this study suggest that the use of Pycnogenol chewing gums can minimize gingival bleeding and plaque accumulation. 相似文献
6.
Spauligodon carbonelli n. sp. (Nematoda: Pharyngodonidae), a parasite from the caecum of the common wall lizard Podarcis muralis (Laurenti, 1768) and the Spanish wall lizard Podarcis hispanica (Steindachner, 1870) (Reptilia: Lacertidae) in the Pirineos Mountains, Spain, is described. S. carbonelli differs from the other known species of the same genus, mainly in the presence and length of the spicule, the morphology of the caudal end in the male and in the structure of the cephalic end of the female. 相似文献
7.
The action spectrum for promotion of elongation of protonemata of Onoclea sensibilis has peaks at 400–420, 580–600 and 640–660 nm. The largest growth increments at saturating light doses are produced by yellow and far-red light. Elongation induced by yellow and far-red irradiation persists in old as well as young filaments, while red-light promotion is found only in young filaments. The growth promotion caused by yellow light is partially reversed by red light down to the level of growth produced by red irradiation alone. Elongation of rhizoids is under reversible red, far-red control, while yellow light is inactive. A model is proposed and discussed in which the light-sensitive elongation of filaments is accounted for by the presence of three distinct photoreceptors: phytochrome; a pigment absorbing yellow light. P580; and a pigment absorbing blue light, P420. 相似文献
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Germinating spores of the fern Onoclea sensibilis L. were grown in darkness, so that they developed as filaments (protonemata). Brief daily exposure of the filaments to red, far-red or blue light increased the rate of filament elongation. Filament elongation was also promoted by indoleacetic acid. When filament elongation was promoted with both indoleacetic acid and exposure to light, the growth promotions caused by red and far-red light were additive to auxin-induced growth. Blue light promoted elongation only at sub-optimal concentrations of auxin. Elongation induced by guanine was additive to red- and far-red-induced elongation. Gibberellic acid had no effect on elongation under any condition. Blue-light-induced elongation resembled auxin-induced elongation in its requirement for exogenous sucrose and sensitivity to inhibition by parachlorophenoxyisobutyric acid. Red and far-red light were active regardless of the presence or absence of sucrose and promoted elongation at a concentration of parachlorophenoxyisobutyric acid which completely inhibited blue-light-induced elongation. 相似文献
10.
Pauline Y. Ladiges M. R. Newnham C. J. Humphries 《Cladistics : the international journal of the Willi Hennig Society》1989,5(4):345-364
Abstract— A cladistic analysis of the "green ash" eucalypts, informal subgenus " Monocalyptus ", is presented- As a first step, ordination methods of principal coordinates analysis and multidimensional scaling delineated some terminal taxa. The cladistic analysis, applying parsimony methods to the unweighted data set, yielded 25 equally parsimonious trees, each with a consistency index of 0.57.
Farris' successive approximations approach to character weighting produced one tree with a consistency index of 0.74.
An informal classification of the group, superseries Eucalyptus , is based on that cladogram. The biogeographic history of superseries Eucalyptus is interpreted from the cladogram as having been caused by lour vicariant events in southeastern Australia, in combination with a suite of ecological features that overlie the biogeographic area-pattern. 相似文献
Farris' successive approximations approach to character weighting produced one tree with a consistency index of 0.74.
An informal classification of the group, superseries Eucalyptus , is based on that cladogram. The biogeographic history of superseries Eucalyptus is interpreted from the cladogram as having been caused by lour vicariant events in southeastern Australia, in combination with a suite of ecological features that overlie the biogeographic area-pattern. 相似文献