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991.
In these experiments we examined whether the elevations in intracellular Ca2+ concentration ([Ca2+]i) induced by methylmercury (MeHg)(described in our previous study) might contribute to cerebellar granule cell mortality following exposure to MeHg in vitro. Cells were exposed to 0.5 microM MeHg for 45 min or 1 microM MeHg for 38 min, conditions previously shown to induce elevations in [Ca2+]i in these cells. Control cells were exposed to buffer alone for 60 min. Viability was assessed using the Live/Dead viability/cytotoxicity kit. At 30 min post-MeHg exposure, there was no immediate increase in cell mortality; however, by 3.5 h after the onset of MeHg exposure, cell viability decreased to 74 and 54% of control values for 0.5 and 1.0 microM MeHg, respectively. At 24.5 h after MeHg exposure, cell viability declined to approximately 27%. Losses in cell viability at 3.5 h were prevented by pretreating the granule cells for 65 min with the Ca2+ chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis(acetoxymethyl)ester (BAPTA; 10 microM), then exposing the cells to MeHg in the continued presence of BAPTA; however, at 24.5 h, BAPTA no longer prevented MeHg-induced cell death. Exposure to the Ca2+ channel blockers omega-conotoxin MVIIC (1 microM) or nifedipine (1 microM), previously shown to delay elevations in [Ca2+]i with MeHg exposure in vitro, protected granule cells from MeHg-induced mortality at 3.5 h postexposure. These data suggest that at early time points, MeHg-induced increases in [Ca2+]i may contribute to granule cell mortality; however, the role of Ca2+ at later time points is unclear. 相似文献
992.
In a retrospective analysis the results of extracorporeal shock wave lithotripsy (ESWL) treatment were evaluated in patients with renal stones according to calyceal localization of treated stones. The 198 patients who underwent ESWL with the Dornier MPL 9000 were analyzed for success rate, complication rate, residual fragments, regrowth and recurrence rates. Totally 210 calyceal calculi located in different portions of the kidney have been comparatively evaluated. No major complications were noted during or after ESWL. Some minor complications such as flank pain, renal colic, haematuria were observed. Flank pain was observed during ESWL treatment especially in patients with upper calyceal stones. Although stone-free and residual fragment rates were similar in pelvic, upper and middle calyces, patients with lower calyceal and pelvicalyceal stones had high residual fragment rate and lower stone-free rate. Patients with stones in the lower calyces or pelvicalyces had high recurrence and regrowth rates (p < 0.05). ESWL has been considered as the optimal treatment modality for most upper urinary tract calculi. It is especially effective in patients with pelvic, upper and middle calyceal stones. Patients with lower calyceal stones often failed to eliminate the fragments, hence had high recurrence and regrowth rates. 相似文献
993.
CM dos Santos ED Moreira EM Krieger LC Michelini 《Canadian Metallurgical Quarterly》1998,31(4):973-977
BACKGROUND: This study was undertaken to determine whether suppression of complement activation with soluble human complement receptor type I reduces myocardial damage during the revascularization of ischemic myocardium. METHODS: In 20 pigs, the second and third diagonal coronary arteries were occluded for 90 minutes, followed by 45 minutes of cardioplegic arrest and 180 minutes of reperfusion. In 10 pigs, soluble human complement receptor type I (10 mg/kg) was infused over 30 minutes before the period of coronary occlusion; 10 other pigs received no soluble human complement receptor type I. Complement activation was measured by total hemolytic complement activity (expressed as a percentage of preischemic values). Ischemic damage was assessed by changes in myocardial tissue pH, wall motion scores (range, 4=normal to -1=dyskinesia), and infarct size (area of necrosis versus area at risk). RESULTS: After 180 minutes of reperfusion, hearts treated with soluble human complement receptor type I had significantly less complement activation than nontreated hearts (1.1%+/-0.09% versus 7.8%+/-0.04%, respectively; p < 0.002), less myocardial acidosis (-0.41+/-0.03 versus -0.72+/-0.03, respectively; p < 0.0001), higher wall motion scores (3.1+/-0.09 versus 1.67+/-0.16, respectively; p < 0.0001), and smaller infarct size (24.6%+/-2.0% versus 41%+/-1.3%, respectively; p < 0.0001). CONCLUSIONS: Complement inhibition with soluble human complement receptor type I significantly limits ischemic damage during the revascularization of acutely ischemic myocardium. 相似文献
994.
C Dumontet N Ketterer D Espinouse EM Neidhardt I Moullet C Thieblemont G Salles B Coiffier 《Canadian Metallurgical Quarterly》1998,21(10):1037-1041
The stability of cisatracurium besylate was studied. Cisatracurium (as besylate) 2 mg/mL in 5- and 10-mL unopened vials and 10 mg/mL in 20-mL unopened vials, as well as 3 mL of solution from additional 2-mg/mL vials, repackaged in 3-mL sealed plastic syringes, was stored at 4 and 23 degrees C in the dark and in normal fluorescent room light. Admixtures of cisatracurium (as besylate) 0.1, 2, or 5 mg/mL in polyvinyl chloride (PVC) minibags of 5% dextrose injection or 0.9% sodium chloride injection were stored at 4 and 23 degrees C in normal fluorescent room light. Triplicate samples for each storage condition were taken initially and at 1, 3, 5, 7, 14, 21, and 30 days; samples from vials were also removed at 45 and 90 days. Solutions were stored in sterile vials at -70 degrees C and then thawed at room temperature before analysis of chemical stability by high-performance liquid chromatography. Physical stability was assessed as well. Cisatracurium besylate was physically stable in all samples throughout the study. Cisatracurium (as besylate) 2 mg/mL exhibited drug losses at 23 degrees C in vials at 45 days and in syringes at 30 days. Cisatracurium (as besylate) 0.1, 2, and 5 mg/mL in 5% dextrose injection and in 0.9% sodium chloride injection was stable for at least 30 days at 4 degrees C, but substantial drug losses occurred at 23 degrees C. Admixtures prepared with cisatracurium (as besylate) 0.1 mg/mL and with 5% dextrose injection exhibited the greatest losses. Cisatracurium besylate was stable in most samples for at least 30 days at 4 and 23 degrees C; admixtures containing cisatracurium (as besylate) 0.1 or 2 mg/mL exhibited substantial drug loss at 23 degrees C. 相似文献
995.
A static or kinetic visual disturbance affects subjects' ability to estimate the direction of the gravitational vertical. This kind of error is increased by a head roll inclination. In two experiments, we combined head orientation with a static (Experiment 1: tilted frame) versus kinetic (Experiment 2: rotating disk) visual disturbance. The results showed that with a static visual disturbance, the increase of errors in the inclined head condition was mainly the consequence of a postural head effect like an Aubert effect. On the contrary, with a kinetic visual disturbance, it appears that the disk effect increases with head inclination. However, individual errors observed with the head inclined in front of a stationary disk were systematically correlated with the errors triggered by the same head inclination in front of a rotating disk. These observations confirm that the head axis spatial reference plays an important role in orientation perception, whatever the head position and the kind of visual display. 相似文献
996.
DF O''neill JF Powell EM Standen JH Youson CM Warby NM Sherwood 《Canadian Metallurgical Quarterly》1998,112(3):415-425
PURPOSE: To measure the compressive forces of the haptics of 28 intraocular lens (IOL) models for different modes of compression and compare the results of two types of measurements. SETTING: Department of Ophthalmology, Central Hospital of Central Finland, Jyv?skyl?, Finland. METHODS: The haptics of 28 types of IOLs were compressed to a diameter of 9.0 mm between curved anvils. The compression forces in the plane of compression (i.e., in the plane of the optics) were measured at 0.5 mm intervals. During compression, the optics and the haptics were free to rotate with respect to the anvils. The results were compared with those of earlier measurements in which the optics were held fixed during compression. Perpendicular forces were measured at 0.4 mm intervals. RESULTS: The measured forces in the plane of the optics varied between 114 and 659 mg at a diameter of 10.0 mm and 192 and 1047 mg at a diameter of 9.0 mm. When compressed to 10.0 mm in diameter, the forces were 1 to 75% lower than when lens rotation was not possible. The forces perpendicular to the optic varied between 0 and 96 mg at a 10.0 mm diameter and correlated with the forces in the plane of the optic. CONCLUSION: The compression forces of the lens haptics were generally lower when the lenses were allowed to rotate during compression. The orders of stiffness of the haptics in these two measurements were similar. The perpendicular forces were generally small and correlated significantly with the forces measured in the plane of the optic. 相似文献
997.
Transient neurophysiological changes in CA3 neurons and dentate granule cells after severe forebrain ischemia in vivo. J. Neurophysiol. 80: 2860-2869, 1998. The spontaneous activities, evoked synaptic responses, and membrane properties of CA3 pyramidal neurons and dentate granule cells in rat hippocampus were compared before ischemia and =7 days after reperfusion with intracellular recording and staining techniques in vivo. A four-vessel occlusion method was used to induce approximately 14 min of ischemic depolarization. No significant change in spontaneous firing rate was observed in both cell types after reperfusion. The amplitude and slope of excitatory postsynaptic potentials (EPSPs) in CA3 neurons decreased to 50% of control values during the first 12 h reperfusion and returned to preischemic levels 24 h after reperfusion. The amplitude and slope of EPSPs in granule cells slightly decreased 24-36 h after reperfusion. The amplitude of inhibitory postsynaptic potentials in CA3 neurons transiently increased 24 h after reperfusion, whereas that in granule cells showed a transient decrease 24-36 h after reperfusion. The duration of spike width of CA3 and granule cells became longer than that of control values during the first 12 h reperfusion. The spike threshold of both cell types significantly increased 24-36 h after reperfusion, whereas the frequency of repetitive firing evoked by depolarizing current pulse was decreased during this period. No significant change in rheobase and input resistance was observed in CA3 neurons. A transient increase in rheobase and a transient decrease in input resistance were detected in granule cells 24-36 h after reperfusion. The amplitude of fast afterhyperpolarization in both cell types increased for 2 days after ischemia and returned to normal values 7 days after reperfusion. The results from this study indicate that the neuronal excitability and synaptic transmission in CA3 and granule cells are transiently suppressed after severe forebrain ischemia. The depression of synaptic transmission and neuronal excitability may provide protection for neurons after ischemic insult. 相似文献
998.
KG Keegan DA Wilson DJ Wilson B Smith EM Gaughan RS Pleasant JD Lillich J Kramer RD Howard C Bacon-Miller EG Davis KA May HS Cheramie WL Valentino PD van Harreveld 《Canadian Metallurgical Quarterly》1998,59(11):1370-1377
OBJECTIVE: To estimate sensitivity and accuracy of subjective evaluation of mild lameness in horses during treadmill locomotion and to correlate subjective evaluation with kinematic analysis. ANIMALS: 19 lame and 5 clinically normal horses. PROCEDURE: Lameness was evaluated by subjective score and kinematic analysis before and after palmar digital nerve block (PDNB). Evaluations were made by 6 clinicians and 7 interns or residents. Within- and between-observer agreement analyses (kappa values) were calculated and compared, using a Student's t-test. Pearson's product-moment correlation coefficients were calculated between clinician's change in score and the change in kinematic variables after PDNB. RESULTS: Within-observer agreement was within the range expected for conditions of moderate diagnostic difficulty. Within-observer agreement was higher for clinicians than for interns or residents. Between-observer agreement was acceptable for scores within 1 value of each other. Between-observer agreement of change in lameness score after PDNB was poor. When kinematic variables were ranked with each clinician's subjective change in score, only 2 were among the top 3 for the majority of clinicians. Asymmetry of vertical head movement between contralateral forelimb stance phases and the point of maximum hoof height during swing decreased as lameness subjectively improved. CONCLUSION: Mild lameness may be difficult to evaluate during treadmill locomotion. Although clinicians were more repeatable in their subjective evaluation of lameness than interns or residents, they were not more reliable at detecting the true state of lameness. CLINICAL RELEVANCE: Lack of agreement between clinician scoring of mild lameness emphasizes the need to use more objective measures for quantifying lameness. 相似文献
999.
KC Parker JI Garrels W Hines EM Butler AH McKee D Patterson S Martin 《Canadian Metallurgical Quarterly》1998,19(11):1920-1932
With the complete sequence of the yeast genome now available, efforts by many laboratories are underway to identify each of the spots on two-dimensional (2-D) gels corresponding to the most abundant yeast proteins. The high mass accuracy now attainable using matrix assisted laser desorption/ionization (MALDI)-mass spectrometry equipped with delayed extraction simplifies the process of identification, such that many spots can be unambiguously identified in a short period of time merely by using peptide mass fingerprinting and generally available database matching programs. Although it is not always possible to match spots between gels run by different laboratories, proteins generally yield the same abundant proteolytic fragments when tryptic digestions are performed. Databases containing these signature peptides not only simplify the task of reidentifying proteins from different gels, but also make it possible to identify small amounts of cross-contaminating proteins from different spots, as well as common extraneous contaminants such as human keratins. In this paper, we present data on the identification of > 20 previously unreported yeast proteins from 2-D gels. Some novel proteins were identified from randomly analyzed spots. Focusing on 14 spots in a narrow-pH-range gel, we demonstrate how organizing peak-table data and peptide match-list data into databases enables the identification of a larger percentage of the peaks. 相似文献
1000.
Hypoglossal motoneurons (HMs) in the caudal brainstem have a respiratory-related activity pattern and contribute to control of upper airway resistance. In this review, we focus primarily on signalling mechanisms utilized by neurotransmitters to enhance HM excitability. In particular, we consider: (1) the membrane depolarization induced by a number of different putative transmitters [thyrotropin-releasing hormone (TRH), serotonin (5-HT), norepinephrine (NE)]; and (2) the inhibition of a calcium-dependent spike after hyperpolarization (AHP) by 5-HT and its effect on firing behavior. Potential functional consequences on HM behavior of these different neurotransmitter effects is discussed. In addition, we describe postnatal changes in transmitter effects and suggest potential cellular mechanisms to explain those developmental changes. Most of the data discussed are derived from in vitro electrophysiological recordings performed in preparations from neonatal and adult rats. 相似文献