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41.
6-Hydroxykynurenic acid and nine flavonol glycosides were isolated and identified from the leaves of GINKGO BILOBA: three of them were identified in Ginkgo for the first time, and two others are unusual P-coumaroyl esters. 相似文献
42.
The thyroid axis and desipramine treatment in depression 总被引:3,自引:0,他引:3
Although there has been much recent investigation of the role of thyroid function in affective illness, few studies have addressed the effects of the tricyclic antidepressants on the pituitary-thyroid axis. In the present study, thyroid functions (TFTs) and thyrotropin-releasing hormone (TRH) stimulation of thyroid-stimulating hormone (TSH) were measured before and after treatment with desipramine (DMI) in 13 men with a diagnosis of major depressive disorder. All subjects had normal TFTs and baseline TSH measured in a drug-free state at the initiation of the study. Both mean free thyroxine index and baseline TSH decreased after DMI treatment. The amount of decrease in baseline TSH correlated with increase in delta TSH. Four subjects had blunted delta TSH (delta TSH less than or equal to 5 microIU/ml); three of these subjects "normalized" with treatment (delta TSH less than or equal to 5 microIU/ml; greater than or equal to 20 microIU/ml). Two subjects had a high delta TSH, and both "normalized" during treatment. The decrease in both free T4 index and TSH suggests a down-regulation of the thyroid axis at the hypothalamic level. "Normalization" of subtle dysregulation of the thyroid axis is suggested as a mechanism of antidepressant therapy in the treatment of some depressions. 相似文献
43.
Heinz Schurawitzki M.D. Paul C. Hajek Josef Kramer Florian Grabenwöger Walter Klepetko Anton Moritz 《Cardiovascular and interventional radiology》1989,12(1):10-13
In a radiologic search for embolized leaflets of Edwards-Duromedics bileaflet valves in 2 patients, the embolized fragments were localized in the iliac vessels using computed tomography. Sonography was successful in one case and standard X-ray films of the abdomen were negative in both cases.In vitro investigations with Björk-Shiley and Edwards-Duromedics leaflets suggested that standard X-ray films of the abdomen and pelvis should be considered as the first investigational technique. If negative, computed tomography of the lower abdomen should be done. 相似文献
44.
Spahn Hildegard Wellstein Anton Pflugmann Gabriele Mutschler Ernst Palm Dieter 《Pharmaceutical research》1989,6(2):152-155
Plasma concentrations of metoprolol after acute and repetitive administration of R/S-metoprolol to healthy volunteers were measured by a -adrenoceptor subtype-specific radioreceptor assay (RRA) and by an enantiospecific high-performance liquid chromatographic (HPLC) method. In the RRA, R/S-metoprolol showed a 20-fold 1-subtype selectivity: the S-( – )-enantiomer was 35-fold more potent than the R-( + )-enantiomer. A comparison between S-( – )-metoprolol concentrations detected in the plasma samples by HPLC and those detected by RRA yielded a 1/1 relationship, indicating that active metabolites are not present to a significant extent. These results were independent of the widely scattering metabolic clearance of metoprolol (with the potential of differences in the rate and extent of formation of active metabolites) in the volunteers. In general, HPLC methods can be validated by comparison with RRA in order to clarify whether active metabolites are present and—on the basis of the Ki value from RRA—whether the detection limit of the physicochemical procedure is sufficient to cover the therapeutically relevant range. 相似文献
45.
Joost B. M. M. van Bree Anne V. Baljet Anton van Geyt Albertus G. de Boer Meindert Danhof Douwe D. Breimer 《Journal of pharmacokinetics and pharmacodynamics》1989,17(4):441-462
The unit impulse response theory has been adapted to characterize the transport profile of drugs into the central nervous system (CNS). From the obtained input function, the cumulative plasma volume (V) cleared by transport into the CNS in time can be calculated. Simulation studies demonstrated that transport governed by passive diffusion resulted in a linear relationship between V and time, while the slope of the line, the blood- brain barrier (BBB) clearance, proved to be an adequate and model independent parameter to characterize drug transport into the CNS. The error in the result of the numerical procedure could be limited to less than 10% of the theoretically predicted value. Superposition of 5 or 10% random noise on simulated data did not result in significant differences between the calculated and theoretically predicted clearance values. Simulations of carrier-mediated transport resulted in nonlinear transport curves; the degree of nonlinearity, and thus the detectability, was dependent on the initial degree of saturation of the system, the rate of desaturation, as caused by drug elimination processes and the noise level on the data. In vivoexperiments in the rat were performed, using atenolol, acetaminophen, and antipyrine as model drugs. Linear transport relationships were obtained for all drugs, indicating that transport was dependent on passive diffusion or a low affinity carrier system. BBB- clearance values were 7±1 l/min for atenolol, 63±7 ul/min for acetaminiphen and 316±25 l/min for antipyrine. These experiments validate the applicability of the presented technique in in vivostudies. 相似文献
46.
Several past studies have reported reliable changes in reaction time performance and self-rated withdrawal scores as a consequence of cigarette deprivation. The purpose of the present study was to determine, prospectively, the effect 24 h of smokeless tobacco deprivation in regular users has on performance and the associated withdrawal symptomology. Forty smokeless tobacco users (Copenhagen brand) were randomly divided evenly into two groups gen brand) were randomly divided evenly into two groups (N=20)24 h of deprivation and no deprivation. A third group of ten nonchewers was added as another control group. The results indicated that behavioral, subjective and physiological changes are associated with smokeless tobacco deprivation in regular users. These include increased craving scores, reaction time, self-rated withdrawal symptoms and decreased heart rate. 相似文献
47.
Verschuren MC; Blom B; Bogers AJ; Spits H; van Dongen JJ 《International immunology》1998,10(12):1873-1880
Recombination of deltaRec to psiJalpha will delete the TCR delta gene,
which is thought to play an important role in the bifurcation of the TCR
alphabeta versus TCR gammadelta differentiation lineages. We recently
detected a DNA-binding protein in human thymocytes, the so- called PJA-BP,
which recognizes the psiJalpha gene segment and might be one of the factors
involved in the regulation of preferential deltaRec- psiJalpha
rearrangements. We now investigate PJA-BP expression and its correlation
with TCR delta gene deletion in thymocytes. Our electrophoretic mobility
shift assay experiments showed that the PJA-BP is evolutionary conserved in
human, murine and simian thymocytes. Using a large series of human
hematopoietic malignancies (n = 30), we conclude that PJA-BP expression is
thymocyte specific and seems to be restricted to thymocytes committed to
the TCR alphabeta lineage. Analysis of seven well-defined human thymocyte
subpopulations showed that preferential deltaRec-psiJalpha rearrangements
as well as PJA-BP expression can be detected from the immature
CD34-/CD1+/CD3- /CD4+/CD8alpha+beta- thymocyte differentiation stage
onwards. These experiments indicate that expression of PJA-BP in human
thymocytes starts simultaneously with preferential deltaRec-psiJalpha
rearrangements, which supports our hypothesis that PJA-BP is one of the
factors involved in the preferential recombination of deltaRec to
psiJalpha.
相似文献
48.
Genetic mapping ofPim-1 putative oncogene to mouse chromosome 17 总被引:10,自引:0,他引:10
John Hilkens H. Theo Cuypers Gerard Selten Vera Kroezen Jo Hilgers Anton Berns 《Somatic Cell and Molecular Genetics》1986,12(1):81-88
Pim-1 is a putative oncogene activated in T-cell lymphomas induced by Moloney and AKR mink cell focus forming (MCF) viruses. We have determined the chromosomal localization of the Pim-1gene in mice by Southern blot analysis of DNAs obtained from a panel of mouse-Chinese hamster somatic cell hybrids. The Pim-1gene was localized on chromosome 17, a chromosome frequently aberrant in T-cell lymphomas. Two chromosomal regions, containing sequences homologous to regions within the Pim-1locus, were localized on chromosome 6 and 16. 相似文献
49.
Anton A. Apostolov Eliana Bosvelieva Alexander Du Chesne Konstantin Goranov Stoyko Fakirov 《Macromolecular chemistry and physics.》1993,194(8):2267-2277
Isotropic unannealed and annealed melt-pressed and quenched samples of segmented multiblock poly(ether-ester-amide)s based on polyamide-6 and poly(ethylene glycol)s (PEGs) of molecular weights 400 and 1000 with various hard/soft segment weight ratios were investigated. The effect of composition, segment length and annealing temperature on the crystal structure was studied by differential scanning calorimetry, wide-angle and small-angle X-ray scattering. In addition to the γ-phase, one of the unannealed samples having relatively long hard and soft segments exhibits a high amount of α-phase. This is assumed to be due to the high flexibility of the PEG segments, linking the polyamide blocks thus enhancing their mobility. The lack of hydrogen bonds between the PEG segments facilitates crystallization of the polyamide segments in the more perfect α-modification, which is the most pronounced in the above mentioned sample. Part of the α-phase transforms into the α-phase upon annealing in all copolymer samples studied, similarly to polyamide-6. 相似文献
50.
Morphology of cells and hemagglutinogens of Bordetella species: resolution of substructural units in fimbriae of Bordetella pertussis. 总被引:1,自引:7,他引:1
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The morphology of cells and the hemagglutinogens isolated from cultures of Bordetella pertussis, Bordetella bronchiseptica, and Bordetella parapertussis were studied by electron microscopy with the negative-staining technique. Cells of all three species had long, thin (3 nm thick), peritrichously arranged fimbriae on the cell surface. Similar structures were found in purified hemagglutinogen preparations together with shorter fimbrial structures 3 nm thick and from 40 to 100 nm long. In one experiment, long, thin fimbriae isolated from B. pertussis were found to be arranged in a crystalline structure on the specimen grid after negative staining. Optical diffraction analysis with a filtering technique performed on micrographs of these structures revealed 12.5-nm-long substructures within individual fimbriae. Further analysis resolved each of these structures into three globules, a central globule 3.5 nm in diameter and two diametrically opposed globules 2.5 nm in diameter. Based on this substructural composition, it is suggested that subunits of the individual fimbriae are connected by fragile regions. The presence of such regions would explain the size heterogeneity of the filamentous structures observed in preparations of hemagglutinogens isolated from cultures of B. pertussis and B. bronchiseptica. The concept that the short filamentous structures present in purified preparations of hemagglutinogens originate from the surface fimbriae present on the cells is supported. 相似文献