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Juraj Sprung MD PhD David Distel CRNA Jeffrey Grass MD Eric L. Bloomfield MD Ian C. Lavery MD 《Journal of clinical anesthesia》1996,8(8):662-665
We describe a patient in whom long-term monoamine oxidase (MAO) inhibitor therapy was discontinued 20 days before surgery with general anesthesia. This patient developed severe perioperative hypotension after administration of 10 mg of bupivacaine through an epidural catheter, which was corrected only after potent vasopressor therapy. We attribute this hemodynamic instability to attenuation of this patient's sympathetic tone based on several mechanisms: (1) residual effect of long-term administration of MAO inhibitor that caused a decrease in the number of β-adrenergic receptors (adrenergic subsensitivity due to receptor down-regulation), (2) recovered MAO activity causing effective degradation of sympathetic amines, and (3) combined attenuating effects of general and epidural anesthesia on sympathetic tone. 相似文献
24.
Ian Fairlie 《Journal of radiological protection》2007,27(2):157-168
An apparent disparity exists between RBE (relative biological effectiveness) values for low-range beta and Auger emitters, and the current value for their radiation weighting factor (w(R)). This paper presents evidence that the current w(R) value of unity for these nuclides is inconsistent with most RBE evidence and should be increased by a factor of two to three. It recommends that the ICRP should clearly state that the most appropriate RBE value for these nuclides, and not the w(R) value, should be used in specific dose calculations, retrospective dose estimations and epidemiological studies. The ICRP should also publish guidance as to the methods and data sources that could be used for these RBE values. 相似文献
25.
A. Ian Smith Catherine A. Wallace Lain J. Clarke John W. Funder 《Journal of neuroendocrinology》1989,1(5):357-362
In the sheep, unlike many other species, a significant proportion (>25%) of immunoreactive β-endorphin in the anterior pituitary is post-translationally modified to opioid-inactive, α-N-acetylated forms. In a study to determine the precise molecular nature of α-N-acetylated β-endorphin immunoreactivity, we noted a striking difference in high-performance liquid chromatography profiles of anterior pituitary extracts between sheep killed on the farm, and age-, sex- and strain-matched slaughterhouse animals. These altered patterns of a-N-acetylated β-endorphin processing were reproduced in farm animals by chronic (≤ 4 days) treatment with the synthetic glucocorticoid dexamethasone; in contrast dexamethasone had no effect on a-N-acetylated β-endorphin processing in hypothalamo-pituitary disconnected sheep. These data suggest that (1) the change in processing is a stress response, mediated by prolonged glucocorticoid exposure, (2) this effect is central, rather than a direct effect on the pituitary, and (3) the relative abundance of various peptide sequences in slaughterhouse-derived material may not reflect their abundance under more physiological conditions. 相似文献
26.
Guoping Lian Mark E Malone Jenny E Homan Ian T Norton 《Journal of controlled release》2004,98(1):139-155
This paper presents a mathematical model of in-mouth volatile release from gelled emulsion particles dispersed in a continuous aqueous phase. Data based on APCI MS-Breath analysis is presented to demonstrate the effect of particle size, oil content and oil-water partition coefficients. It is shown that in-mouth release of aroma from the dispersion of gelled emulsion particles follows a two-component kinetic equation with fast and slow components. Both the fast and slow rate constants depend on the particle size, oil content and oil water partition coefficient of the aroma. The relative amount of aroma contributing to the fast and slow components also depends on the size of the particles. In order to understand this unexpected behaviour, an analytical model was developed that considers the interplay between the mass transfer of flavour across the interface of the particles and that across the air-liquid interface. Analytical expressions for the two rate constants and the relative ratio of aroma contributing to the fast component have been derived. From this model, three regimes of in-mouth release of aroma from the dispersion of gelled emulsion particles were identified including, the emulsion regime, the transition regime and the gel particle regime. In the emulsion regime, changes in the size of gelled emulsion particles had negligible impact on the overall release. In the transition regime, the release was controlled by the interaction of flavour transfer from the particles with that across the air-water interface. In the gel particle regime, aroma release at long times was governed by the particles and that at short times was governed by the air-water interface, and the two processes were fully decoupled. A simple relationship was derived for the critical size above which the release of aroma from the dispersion of gelled emulsion particles is affected by the size of the particles. 相似文献
27.
Dorit Naot Usha Bava Brya Matthews Karen E Callon Gregory D Gamble Michael Black Sarah Song Rocco P Pitto Tim Cundy Jill Cornish Ian R Reid 《Journal of bone and mineral research》2007,22(2):298-309
Paget's disease is a focal condition of bone. To study changes in cells within pagetic lesions, we cultured osteoblasts and stromal cells from 22 patients and compared gene expression in these cells to cells from healthy bone. We identified several differentially regulated genes, and we suggest that these changes could lead to the formation of the lesions. INTRODUCTION: Paget's disease is a focal condition of bone of unknown cause. Although it is regarded as primarily an osteoclast disorder, the tight coupling of the activity of osteoclasts and osteoblasts suggests that the osteoblast could play a key role in its pathogenesis. The aim of the study was to identify possible changes in pagetic osteoblasts and stromal cells that might contribute to the development of pagetic lesions. MATERIALS AND METHODS: Candidate genes were identified based on known bone cell regulators, supplemented with microarray analysis. Gene expression was determined by real-time PCR in primary cultures of osteoblasts and bone marrow stromal cells from pagetic patients and control subjects. Concentrations of secreted proteins were determined by ELISA. RESULTS: Dickkopf1 mRNA and protein levels were increased in both pagetic osteoblast and stromal cell cultures, and interleukin (IL)-1 and IL-6 were overexpressed in pagetic osteoblasts. These changes parallel recent findings in myeloma bone disease, which shares some clinical similarities with Paget's disease. Alkaline phosphatase was overexpressed, and bone sialoprotein and osteocalcin were underexpressed in pagetic osteoblasts, consistent with their circulating levels in pagetic patients. It is hypothesized that overexpression of Dickkopf1, IL-1, and IL-6 would result in stimulation of osteoclast proliferation and inhibition of osteoblast growth, leading to the development of the characteristic lytic bone lesions. By stimulating osteoblast differentiation, Dickkopf1 and IL-6 may also promote mineralization, leading to the conversion of lytic lesions to sclerotic. CONCLUSIONS: These findings suggest that dysregulated gene expression in pagetic osteoblasts could cause the changes in bone cell number and function characteristic of Paget's disease. 相似文献
28.
Chronobiological characteristics of postoperative pain: Diurnal variation of both static and dynamic pain and effects of analgesic therapy 总被引:2,自引:1,他引:1
BACKGROUND: Previous postoperative investigations report morning peaks in analgesic administration. However, few studies have examined diurnal variation of both pain and analgesic consumption and little is known about dynamic pain in this context. METHODS: The diurnal pattern of postoperative pain is described using pain intensity and analgesic consumption data from a recently published hysterectomy trial. RESULTS: In the presence of patient-controlled analgesia with morphine, pain at 8 a.m. was significantly higher (P<0.05) than at noon, 4 p.m. or 8 p.m. on postoperative day one (for rest pain and pain evoked by sitting, forced expiration and cough) and on postoperative day two (for pain evoked by forced expiration and cough only). This temporal pattern was observed both with and without the co-administration of non-opioid analgesics (gabapentin and/or rofecoxib). Morphine use during the four hours preceding 8 a.m. on either postoperative day was not significantly lower than any of the other corresponding time intervals. CONCLUSIONS: Based on data from our post-hysterectomy analgesic clinical trial, static and dynamic pain in the morning appears to be more intense than pain later in the day. This pattern was observed in the presence of substantial nocturnal morphine use. Based on these and other previous observations, specifically designed investigations are needed to better characterize the clinical, neurohormonal and neurophysiological features of postoperative circadian pain variation - including pain during sleeping hours. If the above observations are replicated, future study of nocturnal sustained-release opioids as well as time-shifting the administration of non-opioid co-analgesic drugs to the very early morning may be warranted. 相似文献
29.
CPT Tony Pierson Jeffrey A. Niezgoda MD LT Sarah Learmonth CPT Dennis Blunt LTC Kevin McNabb 《Wound repair and regeneration》2005,13(2):1-2
Abstract Brooke Army Medical Center isolated 25 highly antibiotic‐resistant Acinetobacter ssp . (primarily A. baumannii ) from wounded soldiers returning from Iraq. Concern about effective treatment of these organisms led our institution to begin investigating low‐frequency ultrasound (LFU) as a method of increasing the effectiveness of antibiotics on A.baumannii in wound management. Studies have suggested that LFU applied in conjunction with antibiotics may increase their overall effectiveness. We hypothesize that combining antibiotics with LFU may be an effective method of wound management and that this combination may be synergistic in its overall effect. In this initial work, we wanted to determine if sonocation would have an effect on our organism of interest, A. baumannii . We selected several organisms, both gram positive and gram negative, that have been shown to be killed by sonocation ( E. coli, S. aureus , and S. pyogenes ) and added three highly resistant A. baumannii isolates. Bacterial death was measured by both colony counts after 24 hours of growth and acridine orange staining using a standard protocol.
Colony counts were significantly reduced by sonocation. Furthermore, A.'baumannii colony counts were also greatly reduced by sonocation. Actual cell destruction was also visualized using acridine orange staining. Our data support the assertion that sonocation has an antibacterial effect on some bacteria, including A. baumannii . Our next step is to add antimicrobial agents and determine if their effectiveness can be increased by sonocation. 相似文献
Colony counts were significantly reduced by sonocation. Furthermore, A.'baumannii colony counts were also greatly reduced by sonocation. Actual cell destruction was also visualized using acridine orange staining. Our data support the assertion that sonocation has an antibacterial effect on some bacteria, including A. baumannii . Our next step is to add antimicrobial agents and determine if their effectiveness can be increased by sonocation. 相似文献
30.
Neal R. Barshes Timothy C. Lee Ian W. Udell Christine A. O'Mahoney Beth A. Carter Saul J. Karpen John A. Goss 《American journal of transplantation》2005,5(8):2047-2051
Split liver transplantation (SLT) benefits society by increasing the total number of transplants that can be performed, but it is yet unknown if a decreased post-transplant survival (in comparison to whole liver transplantation) would make participation in SLT less appealing to adult liver transplant candidates. A 20-item questionnaire was administered to 50 adult candidates to assess attitudes toward SLT and organ sharing. The overall attitudes of 60% of participants were classified as utilitarian (maximizing benefit to greatest number of candidates), while 26% were classified as self-preserving (maximizing individual benefit) and 14% were undecided. Ninety percent of participants would be willing to share even if expected survival was less than that of whole liver transplantation, and 69% felt that pediatric candidates should have priority over adult candidates. In conclusion, attitudes toward graft sharing and the possibility of compromised survival benefit are not barriers to SLT for most adult liver transplant candidates. 相似文献