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81.
The catecholamines norepinephrine (NE) and dopamine (DA) have been implicated in the sexual differentiation of brain and behavior and in species-specific learning in several species. To determine if these neurotransmitters might be involved in sexual differentiation of the vocal control system and song learning in male zebra finches, NE and DA levels and turnover rates were quantified in 10 behaviorally relevant brain nuclei [6 vocal control (VCN), 2 auditory (AN), and 2 hypothalamic (HN)] at four critical points during sexual differentiation of the VCN and the period of song learning, 25, 35, 55, and 90 days of age. Some birds were pretreated with alpha-methyl-para-tyrosine (alphaMPT) to allow estimation of NE and DA turnover rates. NE and DA levels in microdissected nuclei were quantified using high-performance liquid chromatography with electrochemical detection. AlphaMPT treatment suppressed catecholamine synthesis just as effectively in juveniles as it does in adults and proved an effective method for estimating NE and DA turnover rates. Patterns of NE and DA function in most VCN and AN over development were quite different from those in HN in which NE and DA function changed gradually and showed no striking peaks. NE turnover rates changed significantly over development in all six VCN [nucleus interfacialis (Nlf), high vocal center (HVC), nucleus robustus of the archistriatum (RA), dorsomedial portion of the intercollicular nucleus (DM), Area X of the parolfactory lobe, and lateral portion of the magnocellular nucleus of the anterior neostriatum (IMAN)]; one AN [nucleus mesencephalicus lateralis pars dorsalis (MLd)], and one HN [preopticus anterior (POA)]. NE levels changed significantly in two VCN (Nlf and Area X). In Nlf, RA, Area X, IMAN, and MLd, NE levels and/or turnover rates showed a striking peak at day 25, which was not seen in HN. Both DA levels and turnover rates changed profoundly over development in 5 of 6 VCN (Nlf, RA, DM, Area X, and IMAN) and both AN (MLd and Field L). These nuclei showed striking peaks in DA levels and turnover rates, primarily on day 35 and/or 55, which then declined profoundly by day 90. This contrasted with the minimal change in DA turnover rates seen in one HN (POA) and the sixth VCN, HVC. In several VCN and AN, NE and DA levels and turnover rates during development reached levels never seen in adult males. Previous research has shown that catecholamine function is heightened in VCN during development compared to surrounding tissues. Our data demonstrate that NE and DA function during development shows pronounced peaks in most VCN not seen in HN. This is interesting because both VCN and HN are hormone sensitive, and both show hormone-modulated NE and DA function in adult males. The timing of these peaks suggests that increased catecholaminergic function may be involved in sexual differentiation of the VCN and song learning in finches. 相似文献
82.
83.
RA Larson RK Dodge CA Linker RM Stone BL Powell EJ Lee P Schulman FR Davey SR Frankel CD Bloomfield SL George CA Schiffer 《Canadian Metallurgical Quarterly》1998,92(5):1556-1564
Recombinant human granulocyte colony-stimulating factor (G-CSF; filgrastim) shortens the time to neutrophil recovery after intensive chemotherapy, but its role in the treatment of adults with acute lymphoblastic leukemia (ALL) is uncertain. We randomly assigned 198 adults with untreated ALL (median age, 35 years; range, 16 to 83) to receive either placebo or G-CSF (5 microgram/kg/d) subcutaneously, beginning 4 days after starting intensive remission induction chemotherapy and continuing until the neutrophil count was >/=1, 000/microL for 2 days. The study assignment was unblinded as individual patients achieved a complete remission (CR). Patients initially assigned to G-CSF then continued to receive G-CSF through 2 monthly courses of consolidation therapy. Patients assigned to placebo received no further study drug. The median time to recover neutrophils >/=1,000/microL during the remission induction course was 16 days (interquartile range [IQR], 15 to 18 days) for the patients assigned to receive G-CSF and 22 days (IQR, 19 to 29 days) for the patients assigned to placebo (P < .001). Patients in the G-CSF group had significantly shorter durations of neutropenia (<1, 000/microL) and thrombocytopenia (<50,000/microL) and fewer days in the hospital (median, 22 days v 28 days; P = .02) compared with patients receiving placebo. The patients assigned to receive G-CSF had a higher CR rate and fewer deaths during remission induction than did those receiving placebo (P = .04 by the chi-square test for trend). During Courses IIA and IIB of consolidation treatment, patients in the G-CSF group had significantly more rapid recovery of neutrophils >/=1,000/microL than did the control group by approximately 6 to 9 days. However, the patients in the G-CSF group did not complete the planned first 3 months of chemotherapy any more rapidly than did the patients in the placebo group. Overall toxicity was not lessened by the use of G-CSF. After a median follow-up of 4. 7 years, there were no significant differences in either the disease-free survival (P = .53) or the overall survival (P = .25) for the patients assigned to G-CSF (medians, 2.3 years and 2.4 years, respectively) compared with those assigned to placebo (medians, 1.7 and 1.8 years, respectively). Adults who received intensive chemotherapy for ALL benefited from G-CSF treatment, but its use did not markedly affect the ultimate outcome. 相似文献
84.
1. Hydroxypropyl-beta-cyclodextrin (HP-beta-CD) increases the stability of the oxazolidine prodrug toward hydrolysis. 2. The binding constant (Kb) and rate constant (Kc) for the hydrolysis of the prodrug-HP-beta-CD complex were calculated from the kinetic data. 3. Ion-spray mass spectra confirmed prodrug-HP-beta-CD complexation. 4. Mass spectral and kinetic data indicated 1:1 stoichiometry for the complex. 5. A significant elevation of locomotor activity in rats was observed when either (-)-ephedrine or the prodrug was administered by either the intraperitoneal or the oral route. 6. Addition of HP-beta-CD potentiated the central nervous system effect of both (-)-ephedrine and the prodrug when administered intraperitoneally. However, when the drugs were administered orally, HP-beta-CD caused a decrease in activity. 相似文献
85.
SC Shim DH Yoo JK Lee HK Koh SR Lee SH Oh SY Kim 《Canadian Metallurgical Quarterly》1998,25(12):2464-2468
Ankylosing spondylitis (AS) results in disease-specific inflammation at the site of ligamentous insertion into the bone. Atlantoaxial joint subluxation and vertical subluxation of the axis may occur as a consequence of instability resulting from the inflammatory process. Spontaneous anterior atlantoaxial subluxation is a well recognized complication in about 2% of patients with AS, and presents with or without signs of spinal cord compression. Vertical subluxation may follow anterior or posterior subluxation. It was noted in 3-8% of patients with rheumatoid arthritis, but is an exceedingly rare complication of AS. Moreover, it has never been reported that multiple cerebellar infarction and bulbar symptoms developed spontaneously due to atlanto-occipital subluxation and vertical subluxation in a patient with a long [corrected] history of AS. We describe a man with AS who developed multiple cerebellar infarction due to vertebral artery obstruction and bulbar symptoms associated with atlanto-occipital subluxation and vertical subluxation. 相似文献
86.
Eernisse EP Ward RW Watts MH Wiggins RB Wood OL 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》1990,37(6):566-570
Experimental results are presented to support the hypothesis that the shape and location of the active region of vibration in a thickness shear mode quartz resonator are the dominant factors in determining the acceleration sensitivity of the resonator. The shape and location of the mode in a real world resonator vary sufficiently from unit to unit (due to material and processing variations) that all other considerations are overwhelmed. It is shown experimentally that the mode shape and/or location can be trimmed with energy trapping by judicious addition or subtraction of mass to produce resonators with improved acceleration sensitivity. 相似文献
87.
88.
Yield-stress measurements on amorphous polyethylene terephthalate film are presented covering five decades of strain rate at temperatures from just below the glass transition ( 60° C) to –160° C. The data were obtained by combining measurements from a conventional Instron machine with data from a high-speed tensile tester capable of applying strain rates of up to 50 sec–1. Five different failure modes have been identified over this extensive range of test conditions. All data from tests which show a clear yield point can be described accurately by an extension of the Ree Eyring approach to include two processes. The process which is only important at low temperatures correlates well with the-process observed in dynamic mechanical experiments. 相似文献
89.
The creep and recovery behaviour of highly drawn polypropylene monofilaments has been studied over the temperature range 20 to 50° C. A range of samples was examined to identify the influence of draw ratio and molecular weight. It is concluded that the permanent flow creep arises from the presence of two thermally activated processes, one of which relates to the -relaxation process and is associated with the crystalline regions of the polymer, and the second with the molecular network. 相似文献
90.
The mineralogy of clay-rich mineral matter isolated from a range of Australian bituminous coals has been evaluated in quantitative terms from X-ray powder diffraction (XRD) patterns using a Rietveld-based data processing technique. The chemical composition of coal ash derived from this mineral matter has been calculated and compared to the directly determined composition of the ash prepared from the same coal samples. Although there are some minor differences due in part to uncertainty regarding the actual composition of several minerals, the compositions indicated by the two methods show a relatively high correlation, suggesting that the Rietveld technique provides mineralogical analyses that are consistent with independently determined chemical data. Comparison of the normalised clay mineral percentages from the Rietveld analysis to quantitative interpretations based on a peak intensities in glycolated and heat-treated oriented aggregates of the respective clay fractions also shows a high correlation, confirming mutual consistency of the two different mineralogical analysis methods. Such quantitative mineralogical data are significant to a range of coal exploration, mining and utilization activities, including seam correlation, material handling and ash and slag formation in combustion processes. 相似文献