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991.
992.
We examined the effects of puff application of endothelin (ET)-1 on the induction of long-term potentiation (LTP) and heterosynaptic long-term depression (LTD) in hippocampal CA1 slices. ET-1 applied 2 min prior to tetanus blocked the induction of LTP, but facilitated the induction of heterosynaptic LTD. These ET-1 effects on synaptic plasticity were dose-dependent, and not due to a generalized depression of baseline responses. ET-1 did not alter NMDA receptor-mediated responses. These data provide the first evidence that endothelin modulates activity-dependent synaptic plasticity, and the potency of these effects suggests that endogenous ET-1 may play an important role in regulating memory storage processes. 相似文献
993.
994.
Y Zhang CM Parsons KE Weingartner WB Wijeratne 《Canadian Metallurgical Quarterly》1993,72(12):2299-2308
Two chick growth experiments and a precision-fed cockerel digestibility assay were conducted to evaluate the effect of extrusion and expelling on the nutritive value of conventional (CSB) and Kunitz trypsin inhibitor-free (KFSB) soybeans. In the first experiment, performance of chicks fed CSB or KFSB autoclaved at 121 C was similar to that of chicks fed CSB or KFSB extruded at 138 C. The effect of extrusion temperature on protein quality of the soybeans was evaluated in the second experiment. Eleven corn-soybean diets were formulated to contain one of the following: CSB extruded at 104, 121, 138, or 154 C; KFSB extruded at 104, 121, or 138 C; CSB extruded at 121, 138, or 154 C followed by processing through an expeller; and commercial dehulled solvent-extracted soybean meal (SBM). All diets contained 20% crude protein and the same amount of soybean oil and were fed to chicks from 7 to 21 days of age. The CSB extruded at 104 or 121 C and KFSB extruded at 104 C yielded depressed growth and feed efficiency compared with SBM. Performance of chicks on the other treatments was similar to that of chicks fed SBM. Pancreas weight (as a percentage of BW) decreased as extrusion temperature increased, with the response being greater for CSB. Growth performance was greater and pancreas weights were lower for chicks fed KFSB extruded at 104 or 121 C compared with those of chicks fed CSB extruded at the same temperatures. Expelling improved weight gain and feed efficiency when CSB was extruded at 121 C. A 48-h digestibility assay with cecectomized cockerels indicated that digestibility of amino acids in CSB and KFSB increased as extrusion temperature increased and that digestibilities of amino acids in CSB extruded at 104 or 121 C were lower than those in KFSB extruded at the same temperatures. Results of this study indicated that extrusion of CSB at 138 to 154 C or extrusion of KFSB at 121 to 138 C yields protein quality similar to that of SBM. 相似文献
995.
The authors describe the technique used in the treatment of autonomously functioning thyroid nodules by percutaneous ethanol injection (PEI). They illustrate the free-hand technique followed in their hospital from January 1990 to October 1992 in a group of 25 patients. Results, advantages and disadvantages of this technique are reported and compared with the ultrasound-guided technique. In the latter, widely used, the needle is positioned in the target nodule by means of an ultrasound probe with a specially designed guiding device which forces the needle in the correct direction. This makes the manoeuver rapid and safe as the needle tip can be easily visualized. In this case, the most important drawback lies in the impossibility of changing the ultrasound scanning plane during the ethanol injection as the probe and the needle are fast together. So the correct spreading modality of ethanol inside the tissue is not completely checked. Another disadvantage is the cost of disposable guiding device necessary in order to avoid contamination. On the other side, in the free-hand technique the needle is aimed at the nodule and inserted during an ultrasound examination without restrain on the probe movements. In this way, it is possible to focus the attention on the critical structures to prevent their damage stopping ethanol injection as soon as a seepage outside the thyroid occurs. Furthermore, this technique is particularly inexpensive as a standard probe is used and the risk of contamination can be avoided by just wrapping the probe with a sterline plastic film.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
996.
CM Crumlish 《Canadian Metallurgical Quarterly》1993,2(4):283-9, 334
There is limited knowledge about how women manage the experience of cardiac surgery. This pilot study examined how women coped with surgery and their emotions in the perioperative period. There was no change in coping or emotion from the day before surgery to the fifth postoperative day, and coping was unrelated to emotion. Preoperative and postoperative confusion and distress were positively correlated. While preliminary, these results raise implications for medical-surgical nursing practice and research. 相似文献
997.
998.
999.
BP Conroy WJ Kraemer CM Maresh SJ Fleck MH Stone AC Fry PD Miller GP Dalsky 《Canadian Metallurgical Quarterly》1993,25(10):1103-1109
The purpose of this study was to examine the relationship of bone mineral density (BMD) to muscular strength in highly trained young male athletes in order to gain insights concerning the influence of heavy resistance training on BMD. Twenty-five elite junior weightlifters (age, 17.4 +/- 1.4 yr) and 11 age-matched controls (16.9 +/- 1.1 yr) volunteered for this investigation. Measurements of BMD (g.cm-2) utilizing dual energy x-ray absorptiometry were obtained for the lumbar spine (L2-4) and the proximal femur (neck; trochanter, Ward's triangle). The BMD values for the junior lifters were found to be significantly greater at all sites for the junior weightlifters compared with their age-matched control group. The BMD values of the spine and femoral neck of the junior weightlifters when compared with adult reference data (i.e., 20-39 yr old men) were found to be significantly greater. Both simple and multiple regression analyses demonstrated significant relationships of BMD with strength accounting for 30-65% of the variance. These data suggest that in elite junior weightlifters, muscle strength, highly specific to the sport of weightlifting, has a major influence on BMD due to the influence of the chronic overloads experienced in training. 相似文献
1000.
The present investigation describes a novel method of demonstrating strain diversity among Pasteurella haemolytica biovar A, serovar 2 (PhA2) nasal turbinate isolates from a flock of 32 experimental goats during a naturally occurring outbreak of pasteurellosis. After a 21 day conditioning period in a feedyard, 51 PhA2 isolates from 27 culture-positive goats were identified including 1 on day 22, 14 on day 25, 21 on day 39, and 15 on day 66. Each PhA2 isolate was evaluated for its enzyme activity against 19 substrates with a commercial semiquantitative enzyme system and for its antimicrobial susceptibility with 12 drugs, resulting in 7 different enzyme profiles and 8 different antimicrobial susceptibility profiles. A total of 14 combined enzyme and antimicrobial susceptibility profiles were produced. The same PhA2 strain was isolated from only 4 of the 12 goats with 2 PhA2 isolations, while the same PhA2 strain was isolated from only 1 of the 6 goats with 3 PhA2 isolations. The data from this investigation demonstrated that the PhA2 upper respiratory tract flora from goats is highly heterologous. 相似文献