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51.
Summary The influence of ethanol on stimulation-evoked 3H-transmitter release was examined in slices of the rat brain cortex and corpus striatum preincubated with 3H-noradrenaline and 3H-choline, respectively. 3H-Transmitter release was stimulated by NMDA, l-glutamate, electrical impulses, reintroduction of Ca2+ ions (Ca2+-evoked release; after superfusion with Ca2+-free, K+-rich solution) or veratridine. In cortical slices preincubated with 3H-noradrenaline and superfused with Mg2+-free, otherwise physiologically composed salt solution, ethanol inhibited the NMDA- or l-glutamate-induced tritium overflow (IC50 45 and 37 mmol/l, respectively). In contrast, the tritium overflow in response to electrical stimulation, reintroduction of Ca2+ ions or veratridine was not affected by ethanol at concentrations up to 320 mmol/l; these experiments were carried out in cortical slices superfused with solution containing a physiological Mg2+ concentration. Ethanol also failed to inhibit Ca2+-evoked release in the absence of Mg2+ ions. In the presence of 1 mol/l veratridine, but not in its absence, NMDA induced tritium overflow even when cortical slices were superfused with salt solution containing a physiological Mg2+ concentration; again, ethanol inhibited this NMDA-evoked tritium overflow (IC50 73 mmol/l). In striatal slices preincubated with 3H-choline and superfused with Mg2+-free physiological salt solution, the NMDA-evoked tritium overflow was also, although at lower potency, inhibited by ethanol (IC50 192 mmol/l).In spite of the differences between the IC50 values of ethanol determined for the inhibition of cortical noradrenaline and striatal acetylcholine release, it may be concluded that the NMDA receptor-ion channel complex is one of the sites of action underlying the ethanol-induced inhibition of neurotransmitter release. Since in the brain cortex the NMDA-induced 3H-noradrenaline release appears to be mediated by an excitatory interneurone activated by NMDA, this neuronal system may be involved in the cortical actions of ethanol. 相似文献
52.
Both M Vogel M Friedrich O von Wegner F Künsting T Fink RH Uttenweiler D 《Journal of biomedical optics》2004,9(5):882-892
We use second harmonic generation (SHG) imaging to study and quantify a strong intrinsic SHG signal in skeletal muscle fiber preparations and single isolated myofibrils. The intrinsic signal follows the striation pattern of the muscle cells and is positioned at the sarcomeric location of the myosin filaments. Interestingly, the signal is enhanced at the region where the myosin heads are located on the myosin filaments. As the intrinsic signal reflects the subcellular structure in an accurate way, SHG can be used for noninvasive high resolution structural imaging without exogenous labels in living muscle cells. This may be very important for detecting changes in myofibrillar organization occurring under pathophysiological conditions, e.g., in cardiac and skeletal myopathies. Due to the strong dependency of SHG on orientation and symmetries of the tissue, it may allow the study of dynamic interactions between the contractile proteins actin and myosin during force production and muscle shortening. Furthermore, SHG imaging can be combined with other nonlinear microscopical techniques, such as laser scanning multiphoton fluorescence microscopy, to simultaneously measure other dynamic cellular processes, representing a complementary method and extending the range of nonlinear microscopical methods. 相似文献
53.
Consecutively admitted internal medical inpatients (N=294) who were psychiatrically assessed with the Schedules for Clinical Assessment in Neuropsychiatry in a two-phase design were followed up in a review of public files on their use of medical care over 18 months. Self-rated outcome was assessed from health and fitness ratings at admission and after 1 year. ICD-10 mental disorders had a statistically significant impact on the risk (odds ratio) of high use (above the 80th percentile) of primary care, as did ICD-10 anxiety/depression, and worry about illness (as assessed by the Whiteley-7 Scale). The authors found a less-than-significant tendency for mental illness to influence the use of inpatient admissions and self-rated outcome. 相似文献
54.
Determination of optimal cryoprotectants and procedures for their addition and removal from human spermatozoa 总被引:9,自引:7,他引:9
The objective was to test the hypothesis that the optimal cryoprotective
agent for cryopreservation of human spermatozoa would be a solute for which
cells have the highest plasma membrane permeability, resulting in the least
amount of volume excursion during its addition and removal. To test this
hypothesis, theoretical simulations were performed using membrane
permeability coefficients to predict optimal procedures for the addition
and removal of a cryoprotectant. Simulations were performed using data from
four different cryoprotectants: (i) glycerol, (ii) dimethyl sulphoxide,
(iii) propylene glycol and (iv) ethylene glycol. Thermodynamic formulations
were applied to determine approaches for the addition and removal of 1 M
and 2 M final concentrations of cryoprotectant, allowing the spermatozoa to
maintain a cell volume within their osmotic tolerance limits. Based on
these data, ethylene glycol was predicted to be optimal for minimizing
volume excursions among the solutes evaluated. These predictions were then
experimentally tested using glycerol as the control cryoprotectant and
ethylene glycol as the experimental cryoprotectant. The results indicate
that there was a higher (P < 0.05) recovery of motile spermatozoa after
cryopreservation when using 1 M ethylene glycol than with 1 M glycerol,
supporting the hypothesis that use of the cryoprotectant for which the cell
has the highest permeability will result in higher cell survival.
相似文献
55.
56.
Donor insemination: Dutch parents' opinions about confidentiality and donor anonymity and the emotional adjustment of their children 总被引:1,自引:4,他引:1
Brewaeys A; Golombok S; Naaktgeboren N; de Bruyn JK; van Hall EV 《Human reproduction (Oxford, England)》1997,12(7):1591-1597
Results from a comparative study investigating 38 donor insemination (DI)
Dutch families with 4-8 year old children are presented. The aims of this
study were to investigate parents' opinions on the issues of
confidentiality and donor anonymity, to assess the emotional development of
the children, and to examine in DI families the association between secrecy
with regard to the use of a donor and the emotional adjustment of the
children. The DI families were compared to families with a child conceived
by in-vitro fertilization (IVF) and to families with a naturally conceived
child. Secrecy appeared to be associated with DI and not with IVF: 74% of
the DI parents intended not to inform the child about the way in which
she/he was conceived, whereas none of the IVF parents intended to keep the
secret. Only one set of DI parents and two sets of IVF parents had actually
told the child. As to donor anonymity, a spread of opinions appeared among
DI parents; 57% preferred an anonymous donor, 31% would have liked non-
identifying information about the donor, 9% preferred the donor's identity
to be registered and 3% remained unsure. Parents' major concern was to know
more about the medical/genetic background of the donor. Mothers and fathers
in the DI families differed in their opinions concerning the issues of
confidentiality and donor anonymity: fathers, more often than mothers, were
secretive with regard to the use of a donor and husbands, more often than
their wives, were in favour of donor anonymity. With regard to the
emotional development of the children, more emotional/behavioural problems
were revealed among DI children than among children who were naturally
conceived. No association was found between secrecy and the
emotional/behavioural adjustment of the children.
相似文献
57.
Basic mechanisms of the rat ERG were reinvestigated with contemporary methods of recording and photic stimulation via an optic fiber system connected with a contact lens. Flash stimulation and background illuminance were performed with photometrically defined light stimuli. ERGs recorded in darkness, from dark adapted rats, were similar with those observed in earlier work in which light flashes of much longer duration had been used. Flash stimulation carried out under stepwise increased background illuminance gave new information on the characteristics of oscillatory potentials of the ERG. In general the present observations agreed with the notion that the rods of the rat retina are as sensitive as in man, whereas the cones are functionally less efficient with respect to light sensitivity and temporal resolution. Differences in function of the cones from rat to man have to be kept in mind when using the rat ERG as a model for risk assessment in safety studies. 相似文献
58.
Diagnosis of acute myocardial infarction from sequential enzyme measurements obtained within 12 hours of admission to hospital. 下载免费PDF全文
P O Collinson E M Ramhamadany S B Rosalki J Joffe D H Evans R S Fink T W Greenwood I M Baird 《Journal of clinical pathology》1989,42(11):1126-1131
A prospective study was made of sequential changes in serum creatine kinase (CK) and CK-MB isoenzyme activity within the 12 hours following admission to the coronary care unit on 65 patients with recent chest pain. CK determinations were performed in the laboratory or in the coronary care unit using a dry reagent strip analyser. Slope values for log CK/hour and log CK-MB/hour were calculated, used to confirm or exclude the diagnosis of myocardial infarction, and compared with diagnosis by conventional means. Compared with retrospective diagnosis using all available information, the CK slope had a sensitivity of 100% and a specificity of 94%. This compared with a sensitivity of 94% and specificity of 90% for diagnosis using upper reference limits alone. Determination of CK slope permits very rapid and accurate biochemical confirmation or exclusion of myocardial infarction and the possibility of performing the measurements on the coronary care unit. It additionally offers the prospect of major cost savings resulting from early discharge or transfer from the coronary care unit. 相似文献
59.
Lung epithelial cells and extracellular matrix components induce expression of Pneumocystis carinii STE20, a gene complementing the mating and pseudohyphal growth defects of STE20 mutant yeast 下载免费PDF全文
Pneumocystis carinii causes severe pneumonia in immunocompromised hosts. The binding of P. carinii to alveolar epithelial cells and extracellular matrix constituents such as fibronectin and vitronectin is a central feature of infection, which initiates proliferation of the organism. Herein, we demonstrate that P. carinii binding to lung cells specifically alters the gene expression of the organism, regulating fungal growth. Subtractive hybridization was performed to isolate P. carinii genes expressed following binding to mammalian extracellular matrix constituents. P. carinii STE20 (PCSTE20), a gene participating in mating and pseudohyphal growth of other fungi, was identified following adherence to the extracellular matrix constituents fibronectin, vitronectin, collagen, and lung epithelial cells. The expression of PCSTE20 and a related P. carinii mitogen-activated protein kinase (MAPK) kinase gene, also implicated in signaling of mating, were both specifically upregulated by binding to matrix protein. The expression of general cyclin-dependent kinases and other MAPKs not involved in mating pathways were not altered by organism binding. PCSTE20 expression was also strongly enhanced following organism attachment to A549 lung epithelial cells. When expressed in a Saccharomyces cerevisiae ste20Delta mutant, PCSTE20 suppressed defects in both mating and pseudohyphal growth. These findings are consistent with the observed proliferation and filopodial extension of Pneumocystis organisms adherent to the epithelium in the lungs of immunocompromised hosts. PCSTE20 expression appears to represent a significant component in the regulation of the life cycle of this intractable opportunistic pathogen. 相似文献
60.