1
|
Wan S, LeClerc JL, Vincent JL. Inflammatory response to cardiopulmonary bypass: mechanisms involved and possible therapeutic strategies. Chest 1997; 112:676-92. [PMID: 9315800 DOI: 10.1378/chest.112.3.676] [Citation(s) in RCA: 603] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Recent study of the inflammatory reactions occurring during and after cardiopulmonary bypass (CPB) has improved our understanding of the involvement of the inflammatory cascade in perioperative injury. However, the exact mechanisms of this complex response remain to be fully determined. METHODS Literature on the inflammatory response to CPB was reviewed to define current knowledge on the possible pathways and mediators involved, and to discuss recent developments of therapeutic interventions aimed at attenuating the inflammatory response to CPB. RESULTS CPB has been shown to induce complement activation, endotoxin release, leukocyte activation, the expression of adhesion molecules, and the release of many inflammatory mediators including oxygen-free radicals, arachidonic acid metabolites, cytokines, platelet-activating factor, nitric oxide, and endothelins. Therapies aimed at interfering with the inflammatory response include the administration of pharmacologic agents such as corticosteroids, aprotinin, and antioxidants, as well as modification of techniques and equipment by the use of heparin-coated CPB circuits, intraoperative leukocyte depletion, and ultrafiltration. CONCLUSIONS Improved understanding of the inflammatory reactions to CPB can lead to improved patient outcome by enabling the development of novel therapies aimed at limiting this response.
Collapse
|
Review |
28 |
603 |
2
|
Luo Y, Wan S, Hui D, Wallace LL. Acclimatization of soil respiration to warming in a tall grass prairie. Nature 2001; 413:622-5. [PMID: 11675783 DOI: 10.1038/35098065] [Citation(s) in RCA: 370] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The latest report by the Intergovernmental Panel on Climate Change (IPCC) predicts a 1.4-5.8 degrees C average increase in the global surface temperature over the period 1990 to 2100 (ref. 1). These estimates of future warming are greater than earlier projections, which is partly due to incorporation of a positive feedback. This feedback results from further release of greenhouse gases from terrestrial ecosystems in response to climatic warming. The feedback mechanism is usually based on the assumption that observed sensitivity of soil respiration to temperature under current climate conditions would hold in a warmer climate. However, this assumption has not been carefully examined. We have therefore conducted an experiment in a tall grass prairie ecosystem in the US Great Plains to study the response of soil respiration (the sum of root and heterotrophic respiration) to artificial warming of about 2 degrees C. Our observations indicate that the temperature sensitivity of soil respiration decreases--or acclimatizes--under warming and that the acclimatization is greater at high temperatures. This acclimatization of soil respiration to warming may therefore weaken the positive feedback between the terrestrial carbon cycle and climate.
Collapse
|
|
24 |
370 |
3
|
Abstract
BACKGROUND Video-assisted thoracic surgery (VATS) lobectomy for early lung cancer has been shown to be technically feasible. Comparative studies on laparoscopic versus open procedures indicate that laparoscopy may reduce inflammatory reactions as reflected by the lesser release of cytokines. We investigated the cytokine responses following VATS and conventional lobectomy for clinical stage I lung cancer. METHODS Thirty-six patients with clinical stage I nonsmall cell lung cancer were studied. 18 patients underwent VATS lobectomy and the other 18 by conventional thoracotomy. There were no differences between the two groups with respect to age, gender, pulmonary function, smoking history, comorbidity, tumor size, and pathology. Plasma levels of tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta, IL-6, IL-8, and an antiinflammatory cytokine IL-10 were measured before surgery, at the end of the procedure, and 4, 8, 24, and 48 hours thereafter in all patients. RESULTS There was no mortality or major complication in either group. Analgesic requirement was significantly less in the VATS group. Although the release of TNF-alpha and IL-1beta were minimal after surgery in both groups, the levels of IL-6, IL-8, and IL-10 were elevated. IL-6 and IL-8 levels were significantly lower in the VATS group at the end of surgery than in the open group. In addition, reduced release of IL-10 was also observed in the VATS group shortly after surgery. CONCLUSIONS VATS lobectomy is associated with reduced postoperative release of both proinflammatory and antiinflammatory cytokines compared with the open approach. The clinical significance of these findings remains to be fully elucidated.
Collapse
|
Comparative Study |
25 |
289 |
4
|
Northover J, Glynne-Jones R, Sebag-Montefiore D, James R, Meadows H, Wan S, Jitlal M, Ledermann J. Chemoradiation for the treatment of epidermoid anal cancer: 13-year follow-up of the first randomised UKCCCR Anal Cancer Trial (ACT I). Br J Cancer 2010; 102:1123-8. [PMID: 20354531 PMCID: PMC2853094 DOI: 10.1038/sj.bjc.6605605] [Citation(s) in RCA: 280] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Background: The first UKCCCR Anal Cancer Trial (1996) demonstrated the benefit of chemoradiation over radiotherapy (RT) alone for treating epidermoid anal cancer, and it became the standard treatment. Patients in this trial have now been followed up for a median of 13 years. Methods: A total of 577 patients were randomised to receive RT alone or combined modality therapy using 5-fluorouracil and mitomycin C. All patients were scheduled to receive 45 Gy by external beam irradiation. Patients who responded to treatment were recommended to have boost RT, with either an iridium implant or external beam irradiation. Data on relapse and deaths were obtained until October 2007. Results: Twelve years after treatment, for every 100 patients treated with chemoradiation, there are an expected 25.3 fewer patients with locoregional relapse (95% confidence interval (CI): 17.5–32.0 fewer) and 12.5 fewer anal cancer deaths (95% CI: 4.3–19.7 fewer), compared with 100 patients given RT alone. There was a 9.1% increase in non-anal cancer deaths in the first 5 years of chemoradiation (95% CI +3.6 to +14.6), which disappeared by 10 years. Conclusions: The clear benefit of chemoradiation outweighs an early excess risk of non-anal cancer deaths, and can still be seen 12 years after treatment. Only 11 patients suffered a locoregional relapse as a first event after 5 years, which may influence the choice of end points in future studies.
Collapse
|
Research Support, Non-U.S. Gov't |
15 |
280 |
5
|
Xia J, Wan S. Global response patterns of terrestrial plant species to nitrogen addition. THE NEW PHYTOLOGIST 2008; 179:428-439. [PMID: 19086179 DOI: 10.1111/j.1469-8137.2008.02488.x] [Citation(s) in RCA: 252] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Better understanding of the responses of terrestrial plant species under global nitrogen (N) enrichment is critical for projection of changes in structure, functioning, and service of terrestrial ecosystems. Here, a meta-analysis of data from 304 studies was carried out to reveal the general response patterns of terrestrial plant species to the addition of N. Across 456 terrestrial plant species included in the analysis, biomass and N concentration were increased by 53.6 and 28.5%, respectively, under N enrichment. However, the N responses were dependent upon plant functional types, with significantly greater biomass increases in herbaceous than in woody species. Stimulation of plant biomass by the addition of N was enhanced when other resources were improved. In addition, the N responses of terrestrial plants decreased with increasing latitude and increased with annual precipitation. Dependence of the N responses of terrestrial plants on biological realms, functional types, tissues, other resources, and climatic factors revealed in this study can help to explain changes in species composition, diversity, community structure and ecosystem functioning under global N enrichment. These findings are critical in improving model simulation and projection of terrestrial carbon sequestration and its feedbacks to global climate change, especially when progressive N limitation is taken into consideration.
Collapse
|
Meta-Analysis |
17 |
252 |
6
|
Wan S, Izzat MB, Lee TW, Wan IY, Tang NL, Yim AP. Avoiding cardiopulmonary bypass in multivessel CABG reduces cytokine response and myocardial injury. Ann Thorac Surg 1999; 68:52-6; discussion 56-7. [PMID: 10421114 DOI: 10.1016/s0003-4975(99)00315-x] [Citation(s) in RCA: 201] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Proinflammatory cytokines play a key role in the inflammatory cascade after cardiopulmonary bypass and may induce cardiac dysfunction. We compared the production of cytokines and the degree of postoperative myocardial injury in patients with multivessel coronary artery disease undergoing coronary artery bypass grafting through median sternotomy with or without cardiopulmonary bypass. METHODS Forty-four consecutive patients were studied. Patients were selected for off-pump coronary artery bypass grafting whenever complete revascularization was technically feasible. There were no differences between the two groups with respect to age, sex, symptoms, or functional class. Plasma levels of tumor necrosis factor-alpha, interleukin (IL)-6, IL-8, and IL-10 were measured before the operation, at the end of the procedure, and 2, 4, 8, 24, and 48 hours thereafter. Levels of the MB isoenzyme of creatine kinase and cardiac troponin-I were also measured after the operation. RESULTS The number of grafts was 2+/-0.7 in the off-pump group (n = 18) and 3+/-0.8 in the cardiopulmonary bypass group (n = 26). There were no deaths or major complications in either group. Levels of tumor necrosis factor-alpha were low in both groups. No significant intergroup differences were noted regarding serial IL-6 measurements. However, IL-8 and IL-10 levels after the operation were lower in the off-pump group (IL-8, 4+/-1 versus 38+/-12 pg/mL, p < 0.01; IL-10, 5+/-2 versus 191+/-33 pg/mL, p < 0.001). Whereas postoperative creatine kinase-MB values were similar in the two groups, cardiac troponin-I levels were significantly lower in the off-pump group (8 hours, p < 0.005; 24 hours, p < 0.02, respectively). Moreover, cardiac troponin-I values 24 hours after operation correlated strongly with IL-8 levels (r = 0.61, p < 0.005), indicating that the degree of myocardial injury may be related to IL-8 production. CONCLUSIONS Compared with conventional coronary artery bypass grafting, coronary revascularization without cardiopulmonary bypass is associated with reduced cytokine responses and less myocardial injury.
Collapse
|
|
26 |
201 |
7
|
Wan S, Parrish JA, Anderson RR, Madden M. Transmittance of nonionizing radiation in human tissues. Photochem Photobiol 1981; 34:679-81. [PMID: 6458827 DOI: 10.1111/j.1751-1097.1981.tb09063.x] [Citation(s) in RCA: 199] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
|
|
44 |
199 |
8
|
Peng S, Piao S, Ciais P, Myneni RB, Chen A, Chevallier F, Dolman AJ, Janssens IA, Peñuelas J, Zhang G, Vicca S, Wan S, Wang S, Zeng H. Asymmetric effects of daytime and night-time warming on Northern Hemisphere vegetation. Nature 2013; 501:88-92. [PMID: 24005415 DOI: 10.1038/nature12434] [Citation(s) in RCA: 194] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Accepted: 07/04/2013] [Indexed: 11/09/2022]
|
|
12 |
194 |
9
|
Wan S, LeClerc JL, Vincent JL. Cytokine responses to cardiopulmonary bypass: lessons learned from cardiac transplantation. Ann Thorac Surg 1997; 63:269-76. [PMID: 8993291 DOI: 10.1016/s0003-4975(96)00931-9] [Citation(s) in RCA: 190] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND A growing body of evidence relates the release during cardiopulmonary bypass (CPB) of proinflammatory cytokines, such as tumor necrosis factor-alpha, interleukin (IL)-6, and IL-8, to the postoperative systemic inflammatory response syndrome. Antiinflammatory cytokines, such as IL-10, however, may also play an important role in limiting these complications. METHODS The English-language literature was reviewed. Emphasis was placed on cytokine responses during clinical CPB for cardiac operations and, in particular, for heart and heart-lung transplantation. RESULTS The recent data indicate that (1) although cytokine release can be triggered by many factors during CPB, ischemia-reperfusion may play the most important role; (2) the levels of tumor necrosis factor-alpha, IL-6, and IL-8 are correlated with the duration of cardiac ischemia and the myocardium is a major source of these three cytokines during CPB; (3) IL-10 levels are correlated with the duration of CPB and the liver is a major source of IL-10 during CPB; and (4) steroid pretreatment is an effective intervention to inhibit the release of proinflammatory cytokines and enhance IL-10 production. CONCLUSIONS The improved knowledge of cytokine responses to CPB may help to develop interventions aimed at reducing postoperative morbidity and mortality.
Collapse
|
Review |
28 |
190 |
10
|
Wan S, DeSmet JM, Barvais L, Goldstein M, Vincent JL, LeClerc JL. Myocardium is a major source of proinflammatory cytokines in patients undergoing cardiopulmonary bypass. J Thorac Cardiovasc Surg 1996; 112:806-11. [PMID: 8800171 DOI: 10.1016/s0022-5223(96)70068-5] [Citation(s) in RCA: 189] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Proinflammatory cytokines, such as tumor necrosis factor-alpha, interleukin-6, and interleukin-8, and anti unflammatory cytokines, such as interleukin-10, may play an important role in patient responses to cardiopulmonary bypass. We sought to define whether the myocardium and the lungs serve as important sources of these cytokines under conditions of cardiopulmonary bypass. Ten patients (age 64 +/- 3 years, mean +/- standard error of the mean) undergoing elective coronary artery bypass grafting were monitored with an arterial catheter, a coronary sinus catheter, and pulmonary artery catheter. Plasma levels of tumor necrosis factor-alpha, interleukin-6, interleukin-8, and interleukin-10 were measured simultaneously in peripheral arterial blood, coronary sinus blood, and mixed venous blood before heparin administration, 1 minute before aortic crossclamping, 5 minutes after aortic declamping, and at 0.5, 1, 1.5 and 2 hours after aortic declamping. The durations of cardiopulmonary bypass and aortic crossclamping were 114 +/- 9 and 64 +/- 5 minutes, respectively. Levels of tumor necrosis factor-alpha and interleukin-6 were significantly higher in coronary sinus blood than in arterial blood after aortic declamping. Tumor necrosis factor-alpha and interleukin-6 levels were also higher in mixed venous blood than in arterial blood within 1 hour after declamping. There were no significant differences among the three sampling sites with respect to interleukin-8 and interleukin-10 levels. In one patient who had postoperative myocardial infarction, however, interleukin-8 levels were three times as high as in coronary sinus blood than in arterial blood. These data indicate that the myocardium is a major source of tumor necrosis factor-alpha and interleukin-6 in patients undergoing cardiopulmonary bypass. The lungs may consume rather than release proinflammatory cytokines in the early phase of reperfusion. The source under these conditions of the antünflammatory cytokine interleukin-10 remains to be determined.
Collapse
|
|
29 |
189 |
11
|
Wan S, Anderson RR, Parrish JA. Analytical modeling for the optical properties of the skin with in vitro and in vivo applications. Photochem Photobiol 1981; 34:493-9. [PMID: 7312955 DOI: 10.1111/j.1751-1097.1981.tb09391.x] [Citation(s) in RCA: 164] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Analytical modeling that interrelates the optical properties of multilayered structures is applied to the skin. The mathematical approach is based on relations of diffuse reflectance and transmittance of a multilayered system and the diffuse reflectance and transmittance of each component layer. The formula can also be derived from the Kubelka-Munk theory of radiation transfer. Using both collimated and diffuse incident irradiance, the applicability of the model to human epidermis over the UV and visible region has been verified. The model has been applied to calculate to absorption and scattering coefficients of human epidermis in vitro, and to estimate the epidermal transmittance under simulated in vivo condition.
Collapse
|
|
44 |
164 |
12
|
Niu S, Wu M, Han Y, Xia J, Li L, Wan S. Water-mediated responses of ecosystem carbon fluxes to climatic change in a temperate steppe. THE NEW PHYTOLOGIST 2008; 177:209-219. [PMID: 17944829 DOI: 10.1111/j.1469-8137.2007.02237.x] [Citation(s) in RCA: 149] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Global warming and a changing precipitation regime could have a profound impact on ecosystem carbon fluxes, especially in arid and semiarid grasslands where water is limited. A field experiment manipulating temperature and precipitation has been conducted in a temperate steppe in northern China since 2005. A paired, nested experimental design was used, with increased precipitation as the primary factor and warming simulated by infrared radiators as the secondary factor. The results for the first 2 yr showed that gross ecosystem productivity (GEP) was higher than ecosystem respiration, leading to net C sink (measured by net ecosystem CO(2) exchange, NEE) over the growing season in the study site. The interannual variation of NEE resulted from the difference in mean annual precipitation. Experimental warming reduced GEP and NEE, whereas increased precipitation stimulated ecosystem C and water fluxes in both years. Increased precipitation also alleviated the negative effect of experimental warming on NEE. The results demonstrate that water availability plays a dominant role in regulating ecosystem C and water fluxes and their responses to climatic change in the temperate steppe of northern China.
Collapse
|
|
17 |
149 |
13
|
Lin D, Xia J, Wan S. Climate warming and biomass accumulation of terrestrial plants: a meta-analysis. THE NEW PHYTOLOGIST 2010; 188:187-98. [PMID: 20609113 DOI: 10.1111/j.1469-8137.2010.03347.x] [Citation(s) in RCA: 146] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
• Growth of terrestrial plant species and functional types (PFTs) in response to climate warming determines future dynamics of terrestrial vegetation. • Here, a meta-analysis was conducted with data collected from 127 publications to reveal general patterns of biomass responses of terrestrial plants to warming. • Warming significantly increased biomass by 12.3% (with a 95% confidence interval of 8.4-16.3%) across all the terrestrial plants included. However, biomass responses were dependent upon PFTs, with significantly greater stimulation of woody (+26.7%) than herbaceous species (+5.2%). Warming effects on biomass showed quadratic relationships with both latitude and mean annual temperature, but did not change with mean annual precipitation or experimental duration. In addition, the other treatments, including CO(2) enrichment, nitrogen addition, drought and water addition, did not alter warming responses of plant biomass. • Dependence of the terrestrial plant biomass responses to warming upon PFTs, geographic and climatic factors as well as warming magnitudes will have consequent influences on community composition and structure, vegetation dynamics, biodiversity and ecosystem functioning in a warmer world. Our findings of functional type-specific responses of terrestrial plants are critical for improving predictions of climate-terrestrial carbon feedbacks.
Collapse
|
Meta-Analysis |
15 |
146 |
14
|
Yano OJ, Morrissey N, Eisen L, Faries PL, Soundararajan K, Wan S, Teodorescu V, Kerstein M, Hollier LH, Marin ML. Intentional internal iliac artery occlusion to facilitate endovascular repair of aortoiliac aneurysms. J Vasc Surg 2001; 34:204-11. [PMID: 11496269 DOI: 10.1067/mva.2001.115380] [Citation(s) in RCA: 136] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
PURPOSE The safety of intentional occlusion of patent internal iliac arteries (IIAs) to facilitate the endovascular repair of aortoiliac artery aneurysms (abdominal aortic aneurysms [AAAs] and iliac aneurysms [IAs]) was evaluated. METHODS We analyzed the techniques and clinical sequelae of selective occlusion of one or both IIAs in 103 patients and correlated these findings with the results of preoperative angiograms to identify vascular anatomy that may predict postoperative pelvic ischemia. To quantify the clinical presentation of pelvic ischemia, we developed these criteria: class 0, no symptoms; class I, nonlimiting claudication with exercise; class II, new onset impotence, with or without moderate to severe buttock pain, leading to physical limitation with exercise; class III, buttock rest pain, colonic ischemia, or both. IIA occlusion was achieved in 100% of the patients by means of either catheter-directed embolization or orificial coverage with a stent-graft. No patient in this study had angiographic evidence of significant visceral occlusive disease before the procedure. Sixty-four patients had isolated AAAs, 23 patients had AAAs and IAs, and 16 patients had isolated IAs. Ninety-two patients had one IIA selectively occluded, and 11 patients had both IIAs selectively occluded. RESULTS After IIA occlusion, 12 patients were categorized in class I, 9 patients were categorized in class II, and 1 patient was categorized in class III, for a total of 22 patients (21%) with pelvic ischemia. Sixteen (17%) of 92 patients had unilateral IIA occlusions, and six (17%) of 11 patients had bilateral IIA occlusions. Five patients in class I improved and had no symptoms within 1 year, and one patient in class II was downgraded to class I because of improved symptoms. Two unique preoperative angiographic findings were identified in the remaining 16 patients (16%) with chronic pelvic claudication: (1) stenosis of the remaining IIA origin (> 70%) with nonopacification of more than three of the six IIA branches (63%); and (2) small caliber, diseased or absent medial and lateral femoral circumflex arteries ipsilateral to the side of the IIA occlusion (25%). One patient with class III ischemia died of cardiovascular collapse associated with colon infarction caused by either acute ischemia or particulate embolization. CONCLUSION The incidence of pelvic ischemia after IIA occlusion is 20% immediately after endovascular aortoiliac aneurysm repair. A total of 25% of patients had no symptoms within 1 year. Two preoperative radiologic findings may help identify patients who are at risk for pelvic ischemia: stenosis of the patent IIA and disease deep femoral ascending branches ipsilateral to the occluded IIA. The risk of colon ischemia appears to be small after selective IIA occlusion to facilitate endovascular AAA repair.
Collapse
|
|
24 |
136 |
15
|
Wan S, Marchant A, DeSmet JM, Antoine M, Zhang H, Vachiery JL, Goldman M, Vincent JL, LeClerc JL. Human cytokine responses to cardiac transplantation and coronary artery bypass grafting. J Thorac Cardiovasc Surg 1996; 111:469-77. [PMID: 8583822 DOI: 10.1016/s0022-5223(96)70458-0] [Citation(s) in RCA: 129] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Cardiac surgery with cardiopulmonary bypass triggers an inflammatory response involving proinflammatory cytokines such as tumor necrosis factor-alpha, interleukin-6, and interleukin-8. To elucidate the pathophysiology of this cytokine response, we explored the possible differences in cytokine responses between patients undergoing heart transplantation and those undergoing coronary artery bypass grafting. Plasma levels of tumor necrosis factor-alpha, interleukin-6, interleukin-8, and interleukin-10 were measured in eight patients undergoing heart transplantation (mean age 44 years) and eight patients undergoing coronary artery bypass grafting (mean age 61 years). Duration of cardiopulmonary bypass and ischemic time were both longer in the heart transplantation group than in the coronary artery bypass grafting group (133 +/- 26 min vs 100 +/- 31 min, p < 0.05, and 130 +/- 47 min vs 58 +/- 21 min, p < 0.005, respectively). Samples were collected before heparin administration, at aortic crossclamping and declamping, and at 0.5, 1, 1.5, 2, 4, 12, and 24 hours after declamping. Tumor necrosis factor-alpha levels were significantly higher 30 minutes after aortic declamping in the heart transplantation group than in the coronary artery bypass grafting group (68 +/- 30 vs 18 +/- 5 pg/ml, p < 0.05). Interleukin-6 and interleukin-8 levels were also significantly higher 90 minutes after declamping in patients undergoing heart transplantation than in those undergoing coronary artery bypass grafting (310 +/- 63 vs 169 +/- 24 pg/ml, p < 0.05, and 73 +/- 17 vs 24 +/- 5 pg/ml, p < 0.01, respectively). Furthermore, interleukin-6 and interleukin-8 values 90 minutes after declamping were significantly correlated with the ischemic time (r = 0.72 and r = 0.82, respectively, both p < 0.05). Interleukin-10 levels in both groups rose to reach a peak value of around 115 pg/ml 1 hour after declamping. Patients undergoing heart transplantation exhibited a second peak of tumor necrosis factor-alpha, interleukin-8, and interleukin-10 levels 12 hours after declamping, probably related to the administration of rabbit antihuman thymocyte immunoglobulin (Thymoglobuline) 3 hours after declamping. Interleukin-6 levels decreased more significantly 12 and 24 hours after declamping in patients undergoing heart transplantation, probably related to methylprednisolone therapy. In conclusion, cardiopulmonary bypass is associated with the production of both proinflammatory and antiinflammatory cytokines. The production of proinflammatory cytokines in patients undergoing heart transplantation is higher than that in patients undergoing coronary artery bypass grafting, and this increase could be related to the longer duration of ischemia in the former group. The later course of cytokine levels after heart transplantation may be further influenced by immunosuppressive therapy.
Collapse
|
Clinical Trial |
29 |
129 |
16
|
Wan S, Xia J, Liu W, Niu S. Photosynthetic overcompensation under nocturnal warming enhances grassland carbon sequestration. Ecology 2009; 90:2700-10. [PMID: 19886480 DOI: 10.1890/08-2026.1] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A mechanistic understanding of the carbon (C) cycle-climate change feedback is essential for projecting future states of climate and ecosystems. Here we report a novel field mechanism and evidence supporting the hypothesis that nocturnal warming in a temperate steppe ecosystem in northern China can result in a minor C sink instead of a C source as models have predicted. Nocturnal warming increased leaf respiration of two dominant grass species by 36.3%, enhanced consumption of carbohydrates in the leaves (72.2% and 60.5% for sugar and starch, respectively), and consequently stimulated plant photosynthesis by 19.8% in the subsequent days. Our experimental findings confirm previous observations of nocturnal warming stimulating plant photosynthesis through increased draw-down of leaf carbohydrates at night. The enhancement of plant photosynthesis overcompensated the increased C loss via plant respiration under nocturnal warming and shifted the steppe ecosystem from a minor C source (1.87 g C x m(-2) x yr(-1)) to a C sink (21.72 g C x m(-2) x yr(-1)) across the three growing seasons from 2006 to 2008. Given greater increases in daily minimum than maximum temperature in many regions, plant photosynthetic overcompensation may partially serve as a negative feedback mechanism for terrestrial biosphere to climate warming.
Collapse
|
Research Support, Non-U.S. Gov't |
16 |
114 |
17
|
Sihoe AD, Yim AP, Lee TW, Wan S, Yuen EH, Wan IY, Arifi AA. Can CT scanning be used to select patients with unilateral primary spontaneous pneumothorax for bilateral surgery? Chest 2000; 118:380-3. [PMID: 10936128 DOI: 10.1378/chest.118.2.380] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
STUDY OBJECTIVES Despite advances in the surgical treatment of spontaneous pneumothorax, the timing of surgical intervention continues to be a subject of controversy. We test the hypothesis that CT scanning can help to predict the probability of the occurrence of primary spontaneous pneumothorax (PSP) by detecting lung bullae. DESIGN Prospective, longitudinal cohort study. PATIENTS AND METHODS Between May 1994 to March 1995, 28 consecutive patients (23 men; age range, 18 to 47 years; mean, 29 years) with unilateral PSP who were to undergo video-assisted thoracic surgery (VATS) received preoperative CT of the thorax. CT scans were interpreted by one radiologist blinded to the clinical data for the presence of bullae in both lungs. All patients were followed-up in our outpatient clinic for an average of 59.0 months (range, 54 to 64 months). RESULTS Eighty-eight percent of the blebs or bullae identified intraoperatively were demonstrated on preoperative CT scans. CT scans also showed the presence of lung blebs or bullae in the contralateral lung in 15 patients (53.6%). During the follow-up period, 4 of these 15 patients (26.7%) with contralateral blebs developed PSP in the untreated lung; none of the patients who did not have contralateral blebs (n = 13) developed PSP (p = 0.04 [chi(2) analysis]). CONCLUSIONS The detection of lung bullae by CT scanning in the contralateral lung following unilateral PSP is associated with a higher rate of subsequent occurrence of pneumothorax in that lung. Thus, CT scanning can be used to predict the risk of occurrence of this condition, allowing preemptive surgical intervention in selected patients.
Collapse
|
Comparative Study |
25 |
96 |
18
|
Yang H, Jiang L, Li L, Li A, Wu M, Wan S. Diversity-dependent stability under mowing and nutrient addition: evidence from a 7-year grassland experiment. Ecol Lett 2012; 15:619-26. [PMID: 22487498 DOI: 10.1111/j.1461-0248.2012.01778.x] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Anthropogenic perturbations may affect biodiversity and ecological stability as well as their relationships. However, diversity-stability patterns and associated mechanisms under human disturbances have rarely been explored. We conducted a 7-year field experiment examining the effects of mowing and nutrient addition on the diversity and temporal stability of herbaceous plant communities in a temperate steppe in northern China. Mowing increased population and community stability, whereas nutrient addition had the opposite effects. Stability exhibited positive relationships with species richness at population, functional group and community levels. Treatments did not alter these positive diversity-stability relationships, which were associated with the stabilising effect of species richness on component populations, species asynchrony and portfolio effects. Despite the difficulty of pinpointing causal mechanisms of diversity-stability patterns observed in nature, our results suggest that diversity may still be a useful predictor of the stability of ecosystems confronted with anthropogenic disturbances.
Collapse
|
Research Support, U.S. Gov't, Non-P.H.S. |
13 |
93 |
19
|
Abstract
The central role of lung ischaemia-reperfusion injury in pulmonary dysfunction after cardiac surgery, particularly thoracic organ transplantation, has been well recognised. Lung tissue necrosis after prolonged ischaemia is known to worsen lung function, which was believed to be due largely to adjacent tissue inflammation. Recent studies suggest that lung apoptosis following ischaemia-reperfusion could be equally important in the development of post-operative lung dysfunction. The current literature on the mechanism and pathways involved in pulmonary dysfunction and, in particular, its relationship with apoptosis after lung ischaemia-reperfusion is briefly reviewed here. A better understanding of lung apoptosis, as well as the upstream pathways, may help in the development of therapeutic strategies that could benefit patients undergoing cardiac and lung transplantation.
Collapse
|
|
20 |
87 |
20
|
Liu L, Wang X, Lajeunesse MJ, Miao G, Piao S, Wan S, Wu Y, Wang Z, Yang S, Li P, Deng M. A cross-biome synthesis of soil respiration and its determinants under simulated precipitation changes. GLOBAL CHANGE BIOLOGY 2016; 22:1394-405. [PMID: 26554753 DOI: 10.1111/gcb.13156] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 10/20/2015] [Accepted: 10/31/2015] [Indexed: 05/17/2023]
Abstract
Soil respiration (Rs) is the second-largest terrestrial carbon (C) flux. Although Rs has been extensively studied across a broad range of biomes, there is surprisingly little consensus on how the spatiotemporal patterns of Rs will be altered in a warming climate with changing precipitation regimes. Here, we present a global synthesis Rs data from studies that have manipulated precipitation in the field by collating studies from 113 increased precipitation treatments, 91 decreased precipitation treatments, and 14 prolonged drought treatments. Our meta-analysis indicated that when the increased precipitation treatments were normalized to 28% above the ambient level, the soil moisture, Rs, and the temperature sensitivity (Q10) values increased by an average of 17%, 16%, and 6%, respectively, and the soil temperature decreased by -1.3%. The greatest increases in Rs and Q10 were observed in arid areas, and the stimulation rates decreased with increases in climate humidity. When the decreased precipitation treatments were normalized to 28% below the ambient level, the soil moisture and Rs values decreased by an average of -14% and -17%, respectively, and the soil temperature and Q10 values were not altered. The reductions in soil moisture tended to be greater in more humid areas. Prolonged drought without alterations in the amount of precipitation reduced the soil moisture and Rs by -12% and -6%, respectively, but did not alter Q10. Overall, our synthesis suggests that soil moisture and Rs tend to be more sensitive to increased precipitation in more arid areas and more responsive to decreased precipitation in more humid areas. The responses of Rs and Q10 were predominantly driven by precipitation-induced changes in the soil moisture, whereas changes in the soil temperature had limited impacts. Finally, our synthesis of prolonged drought experiments also emphasizes the importance of the timing and frequency of precipitation events on ecosystem C cycles. Given these findings, we urge future studies to focus on manipulating the frequency, intensity, and seasonality of precipitation with an aim to improving our ability to predict and model feedback between Rs and climate change.
Collapse
|
|
9 |
83 |
21
|
Wan S, Coleman FH, Travagli RA. Glucagon-like peptide-1 excites pancreas-projecting preganglionic vagal motoneurons. Am J Physiol Gastrointest Liver Physiol 2007; 292:G1474-82. [PMID: 17322063 DOI: 10.1152/ajpgi.00562.2006] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Glucagon-like peptide-1 (GLP-1) increases pancreatic insulin secretion via a direct action on pancreatic beta-cells. A high density of GLP-1-containing neurons and receptors is also present in brain stem vagal circuits; therefore, the aims of the present study were to investigate 1) whether identified pancreas-projecting neurons of the dorsal motor nucleus of the vagus (DMV) respond to exogenously applied GLP-1, 2) the mechanism(s) of action of GLP-1, and 3) whether the GLP-1-responsive neurons (putative modulators of endocrine secretion) could be distinguished from DMV neurons responsive to peptides that modulate pancreatic exocrine secretion, specifically pancreatic polypeptide (PP). Whole cell recordings were made from identified pancreas-projecting DMV neurons. Perfusion with GLP-1 induced a concentration-dependent depolarization in approximately 50% of pancreas-projecting DMV neurons. The GLP-1 effects were mimicked by exendin-4 and antagonized by exendin-(9-39). In approximately 60% of the responsive neurons, the GLP-1-induced depolarization was reduced by tetrodotoxin (1 microM), suggesting both pre- and postsynaptic sites of action. Indeed, the GLP-1 effects were mediated by actions on potassium currents, GABA-induced currents, or both. Importantly, neurons excited by GLP-1 were unresponsive to PP and vice versa. These data indicate that 1) GLP-1 may act on DMV neurons to control pancreatic endocrine secretion, 2) the effects of GLP-1 on pancreas-projecting DMV neurons are mediated both via a direct excitation of their membrane as well as via an effect on local circuits, and 3) the GLP-1-responsive neurons (i.e., putative endocrine secretion-controlling neurons) could be distinguished from neurons responsive to PP (i.e., putative exocrine secretion-controlling neurons).
Collapse
|
|
18 |
66 |
22
|
Ren H, Xu Z, Isbell F, Huang J, Han X, Wan S, Chen S, Wang R, Zeng DH, Jiang Y, Fang Y. Exacerbated nitrogen limitation ends transient stimulation of grassland productivity by increased precipitation. ECOL MONOGR 2017. [DOI: 10.1002/ecm.1262] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
|
8 |
62 |
23
|
Wan S, Capasso H, Walworth NC. The topoisomerase I poison camptothecin generates a Chk1-dependent DNA damage checkpoint signal in fission yeast. Yeast 1999; 15:821-8. [PMID: 10407262 DOI: 10.1002/(sici)1097-0061(199907)15:10a<821::aid-yea422>3.0.co;2-#] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The protein kinase Chk1 is essential for the DNA damage checkpoint. Cells lacking Chk1 are hypersensitive to DNA-damaging agents such as UV light and gamma-irradiation because they fail to arrest the cell cycle when DNA damage is generated. Phosphorylation of Chk1 occurs after DNA damage and is dependent on the integrity of the DNA damage checkpoint pathway. We have tested whether a topoisomerase I inhibitor, camptothecin (CPT), generates DNA damage in the fission yeast Schizosaccharomyces pombe that results in Chk1 phosphorylation. We demonstrate that Chk1 is phosphorylated in response to CPT treatment in a time- and dose-dependent manner and that phosphorylation is dependent on an intact DNA damage checkpoint pathway. Furthermore, we show that cells must be actively dividing in order for CPT to generate a Chk1-responsive DNA damage signal. This observation is consistent with a model whereby the cytotoxic event caused by CPT treatment is the production of a DNA double-strand break resulting from the collision of a DNA replication fork with a trapped CPT-topoisomerase I cleavable complex. Cells lacking Chk1 are hypersensitive to CPT treatment, suggesting that the DNA damage checkpoint pathway can be an important determinant for CPT sensitivity or resistance. Finally, as a well-characterized, soluble agent that specifically causes DNA damage, CPT will allow a biochemical analysis of the checkpoint pathway that responds to DNA damage.
Collapse
|
|
26 |
61 |
24
|
Wan S, Hua Y, Keep RF, Hoff JT, Xi G. Deferoxamine reduces CSF free iron levels following intracerebral hemorrhage. ACTA NEUROCHIRURGICA. SUPPLEMENT 2006; 96:199-202. [PMID: 16671454 DOI: 10.1007/3-211-30714-1_43] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Iron overload occurs in brain after intracerebral hemorrhage (ICH). Deferoxamine, an iron chelator, attenuates perihematomal edema and oxidative stress in brain after ICH. We investigated the effects of deferoxamine on cerebrospinal fluid (CSF) free iron and brain total iron following ICH. Rats received an infusion of 100-microL autologous whole blood into the right basal ganglia, then were treated with either deferoxamine (100 mg/kg, i.p., administered 2 hours after ICH and then at 12-hour intervals for up to 7 days) or vehicle. The rats were killed at different time points from 1 to 28 days for measurement of free and total iron. Behavioral tests were also performed. Free iron levels in normal rat CSF were very low (1.1 +/- 0.4 micromol). After ICH, CSF free iron levels were increased at all time points. Levels of brain total iron were also increased after ICH (p < 0.05). Deferoxamine given 2 hours after ICH reduced free iron in CSF at all time points. Deferoxamine also reduced ICH-induced neurological deficits (p < 0.05), but did not reduce total brain iron. In conclusion, CSF free iron levels increase after ICH and do not clear for at least 28 days. Deferoxamine reduces free iron levels and improves functional outcome in the rat, indicating that it may be a potential therapeutic agent for ICH patients.
Collapse
|
Research Support, N.I.H., Extramural |
19 |
60 |
25
|
Abstract
BACKGROUND Few surgeons worldwide currently perform video-assisted thoracoscopic (VAT) lobectomy. We conducted a questionnaire survey of this selected group of surgeons to gain insight into their current practice. METHODS A survey with 25 questions on VAT lobectomy including operative approaches, techniques, its role in their practice, and limitations were mailed to 45 thoracic surgeons worldwide who are believed to perform this operation. RESULTS Thirty-three completed questionnaires were analyzed. Among those surgeons practicing VAT lobectomy, the vast majority work in an academic or government institution and have at least 5 years of practice experience. Two thirds reported that at least 40% of all their thoracic procedures are currently performed using VAT techniques. However, considerable variations exist regarding preference for VAT lobectomy (one third uses VAT techniques in less than 10% of all lobectomies performed, whereas another third uses it in more than 40% of lobectomies), their approaches to mediastinal and hilar lymph nodes, and their operative techniques. The latter range from a purely endoscopic technique to one that is more appropriately termed minithoracotomy with video-assistance when the surgeons operate primarily by looking through the utility thoracotomy. There were no significant differences in the practices of surgeons working in different continents, except that Asian surgeons were more likely to use suture ligation as opposed to a staple-cutter on pulmonary vessels. CONCLUSIONS Video-assisted thoracoscopic lobectomy is not a unified approach. Considerable variations exist among the small group of surgeons performing this procedure, in their approach to surgical oncology as well as the operative technique. Distinctions in these different operative approaches must be made before one can make a meaningful comparison of results. Different terms should probably be introduced to further clarify the exact techniques used.
Collapse
|
|
27 |
58 |