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Su S, Cui N, Li J, Sun P, Li H, Li Y, Cui Z. Deletion of the BAC sequences from recombinant meq-null Marek's disease (MD) virus increases immunosuppression while maintaining protective efficacy against MD. Poult Sci 2016; 95:1504-1512. [PMID: 26957626 DOI: 10.3382/ps/pew067] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Accepted: 12/28/2015] [Indexed: 11/20/2022] Open
Abstract
Marek's disease virus (MDV) GX0101 is a field strain of MDV with a naturally occurring insertion of the reticuloendotheliosis virus (REV) long terminal repeat (LTR) fragment. Both copies of the meq gene were knocked out in the GX0101 bacterial artificial chromosome (BAC) clone to construct the recombinant virus SC9-1, resulting in a complete lack of pathogenicity and providing better protection against MD than CVI988/Rispens. In the present study, the BAC sequences in SC9-1 were removed using a cre-loxP system, and the virus termed SC9-2. SC9-2 showed a significant increase in replication in vitro and in vivo. There was a significant decrease in chicken weight, immune organ index, and antibody levels compared with those of SC9-1-inoculated chickens. The immune protection index of SC9-2 was similar to that of SC9-1, and the difference was not significant. The results of our studies demonstrate that the SC9-2 virus provides protection in specific pathogen free (SPF) chickens when challenged with a very virulent MDV rMd5, but it induces immunosuppressive effects in SPF chickens.
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Cui N, Mckillop LE, Fisher SP, Oliver PL, Vyazovskiy VV. Long-term history and immediate preceding state affect EEG slow wave characteristics at NREM sleep onset in C57BL/6 mice. Arch Ital Biol 2015; 152:156-68. [PMID: 25828687 DOI: 10.12871/0002982920142310] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The dynamics of cortical activity across the 24-h day and at vigilance state transitions is regulated by an interaction between global subcortical neuromodulatory influences and local shifts in network synchrony and excitability. To address the role of long-term and immediate preceding history in local and global cortical dynamics, we investigated cortical EEG recorded from both frontal and occipital regions during an undisturbed 24-h recording in mice. As expected, at the beginning of the light period, under physiologically increased sleep pressure, EEG slow waves were more frequent and had higher amplitude and slopes, compared to the rest of the light period. Within discrete NREM sleep episodes, the incidence, amplitude and slopes of individual slow waves increased progressively after episode onset in both derivations by approximately 10-30%. Interestingly, at the beginning of NREM sleep episodes slow waves in the frontal and occipital derivations frequently occurred in isolation, as quantified by longer latencies between consecutive slow waves in the two regions. Notably, slow waves during the initial period of NREM sleep following REM sleep episodes were significantly less frequent, lower in amplitude and exhibited shallower slopes, compared to those that occurred in NREM episodes after prolonged waking. Moreover, the latencies between consecutive frontal and occipital NREM slow waves were substantially longer when they occurred directly after REM sleep compared to following consolidated wakefulness. Overall these data reveal a complex picture, where both time of day and preceding state contribute to the characteristics and dynamics of slow waves within NREM sleep. These findings suggest that NREM sleep initiates in a more "local" fashion when it occurs following REM sleep episodes as opposed to sustained waking bouts. While the mechanisms and functional significance of such a re-setting of brain state after individual REM sleep episodes remains to be investigated, we suggest that it may be an essential feature of physiological sleep regulation.
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Rosenberg J, Petrylak D, Abidoye O, Van der Heijden M, Hofman-Censits J, Necchi A, O'Donnell P, Balmanoukian A, Loriot Y, Retz M, Perez-Gracia J, Dawson N, Balar A, Galsky M, Fleming M, Powles T, Cui N, Mariathasan S, Fine G, Dreicer R. 21LBA Atezolizumab in patients (pts) with locally-advanced or metastatic urothelial carcinoma (mUC): Results from a pivotal multicenter phase II study (IMvigor 210). Eur J Cancer 2015. [DOI: 10.1016/s0959-8049(16)31942-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Negoro H, Cui N, Ogawa O, Suadicani S. MP12-19 SPONTANEOUS MICTURITION BEHAVIOR AND CYSTOMETRIC EVALUATION OF BLADDER FUNCTION IN P2X
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RECEPTOR DEFICIENT MICE. J Urol 2015. [DOI: 10.1016/j.juro.2015.02.794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Jia Q, Xia Y, Zhang Q, Wu H, Du H, Liu L, Wang C, Shi H, Guo X, Liu X, Li C, Sun S, Wang X, Zhao H, Song K, Huang G, Wu Y, Cui N, Niu K. Dietary patterns are associated with prevalence of fatty liver disease in adults. Eur J Clin Nutr 2015; 69:914-21. [PMID: 25649235 DOI: 10.1038/ejcn.2014.297] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 12/10/2014] [Indexed: 02/08/2023]
Abstract
BACKGROUND/OBJECTIVES Previous studies have indicated that higher levels of food consumption are associated with fatty liver disease (FLD), but few studies have investigated the relationship between this disease and different dietary patterns. The aim of this cross-sectional study was to examine the association between dietary patterns and FLD in adults. SUBJECTS/METHODS Dietary intakes of participants in the Tianjin were assessed via questionnaire. Factor analysis was used to identify dietary patterns, and FLD was defined as having a FLD diagnosis using liver ultrasonography. Relationships between dietary patterns and FLD were assessed using multiple logistic regression analysis. RESULTS Female participants in the highest quartile of high-carbohydrate/sweet pattern scores had a 2.19-fold greater risk (95% confidence interval (CI), 1.40-3.46) of developing non-alcoholic FLD (NAFLD) than those in the lowest quartile after adjusting for confounding factors. No significant differences were found between any dietary pattern and NAFLD in males. In males, a significantly increasing trend of alcoholic FLD (AFLD) prevalence was associated with increasing high-protein/cholesterol pattern scores (P for trend = 0.03; odds ratio (OR), 2.08; 95% CI, 1.15-3.81) while an increased high-carbohydrate/sweet pattern score appeared protective against AFLD (P for trend = 0.02; OR, 0.55; 95% CI, 0.29-1.00). CONCLUSIONS Our study demonstrates that high-protein/cholesterol pattern scores are associated with higher prevalence of AFLD in males. We also show high-carbohydrate/sweet pattern scores are associated with higher prevalence of NAFLD in females; but, interestingly, this pattern shows a favorable effect on AFLD in males.
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Cui N, Wen PC, Liang Q, Liu HN, Zhang WB, Wang PJ, Guo HY, Ren FZ. Chemical composition of yak colostrum and transient milk. J Anim Physiol Anim Nutr (Berl) 2014; 99:825-33. [PMID: 25545664 DOI: 10.1111/jpn.12282] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 11/20/2014] [Indexed: 11/30/2022]
Abstract
The objective of this study was to assess the changes in the chemical composition of yak colostrum and transient milk. Samples were collected from 12 yaks on days 1, 2, 3, 4, 5, 6 and 7 post-partum (PP). The gross composition, nitrogen fraction distribution, amino acid (AA) profile and fatty acid (FA) profile were analysed. All the components decreased rapidly during the first 3 days except lactose which increased. The ratio of whey protein to casein protein decreased from 46:54 to 17:83 during the first 7 days PP. The content of all the AAs decreased, while the percentages of eight essential AAs in protein of samples increased during the study period. Monounsaturated FAs and polyunsaturated FAs decreased in the first 7 days PP, whereas saturated FAs increased. In conclusion, the changes in chemical composition were remarkable during the first 3 days. The slight variations, happened during the transient period, are not negligible, which also should be taken into account in the development of yak colostrum supplements.
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Ding YP, Liang MF, Ye JB, Liu QH, Xiong CH, Long B, Lin WB, Cui N, Zou ZQ, Song YL, Zhang QF, Zhang S, Liu YZ, Song G, Ren YY, Li SH, Wang Y, Hou FQ, Yu H, Ding P, Ye F, Li DX, Wang GQ. Prognostic value of clinical and immunological markers in acute phase of SFTS virus infection. Clin Microbiol Infect 2014; 20:O870-8. [PMID: 24684627 DOI: 10.1111/1469-0691.12636] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Revised: 03/25/2014] [Accepted: 03/25/2014] [Indexed: 12/23/2022]
Abstract
SFTS virus (SFTSV) is a novel bunyavirus that causes severe fever with thrombocytopenia syndrome (SFTS), an emerging infectious disease that occurred in China in recent years, with an average case fatality rate of 10-12%. Intervention in the early clinical stage is the most effective measure to reduce the mortality rate of disease. To elucidate the natural course of and immune mechanisms associated with the pathogenesis of SFTSV, 59 laboratory-confirmed SFTS patients in the acute phase, who were hospitalized between October 2010 and September 2011, were enrolled in this study, and the patients sera were dynamically collected and tested for SFTSV viral RNA load, 34 cytokines or chemokines and other related laboratory parameters. All clinical diagnostic factors in the acute phase of SFTS were evaluated and assessed. The study showed that the severity of the disease in 11 (18.6%) patients was associated with abdominal pain (p 0.007; OR = 21.95; 95% CI, 2.32-208.11) and gingival bleeding (p 0.001; OR=122.11; 95% CI, 6.41-2328). The IP-10, TNF-α, IL-6, IL-10, granzyme B and HSP70 levels were higher over the 7-8 days in severe cases, accompanied by altered AST, CK and LDH levels. HSP70 (p 0.012; OR=8.29; 95% CI, 1.58-43.40) was independently correlated with the severity of the early acute phase of SFTSV infection. The severity of SFTS can be predicted based on the presence of symptoms such as abdominal pain and gingival bleeding and on the level of HSP70 in the acute phase of the disease.
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Cui N, Shi J, Jia TZ. [Comparative study on kidney tonifying and yang supporting effects of different processed products of Morinda officinalis]. ZHONGGUO ZHONG YAO ZA ZHI = ZHONGGUO ZHONGYAO ZAZHI = CHINA JOURNAL OF CHINESE MATERIA MEDICA 2013; 38:3898-3901. [PMID: 24558872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
To compare the pharmacological effects for tonifying kidney and supporting Yang of different processed products of Morinda officinalis. The oral administration of adenine was performed to establish the kidney-Yang deficiency mice model. Four different processed products, namely M. officinalis, morinda pulp, salt-steamed M. officinalis and licorice-processed M. officinalis, were administered, with Guifu Dihuang pills as the control drug, and mice signs, weight, testicular coefficient, seminal vesicle coefficient, serum testosterone, serum cortisol and serum creatinine as evaluation indexes. The results showed that all of the four processed products of M. officinalis could improve the symptoms of the kidney-Yang deficient mice. Among them, salt-steamed M. officinalis had the most significant effect, which was followed by licorice-processed M. officinalis, morinda pulp and M. officinalis.
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Cui N, Qiao L, Luo J, Chiovelli S. Pitting of carbon steel with banded microstructures in chloride solutions. ACTA ACUST UNITED AC 2013. [DOI: 10.1179/000705900101501263] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Zhao XZ, Cui N, Luo JL, Chiovelli S. Effects of erosion on corrosion of type 430 and 316 stainless steels in aqueous environments. ACTA ACUST UNITED AC 2013. [DOI: 10.1179/000705902225002439] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Lazarou G, Rahimi S, Cui N, Zormpa M. Endoscopic balloon dilation in the management of ureteral stricture after urogynecologic surgery: a case report. THE JOURNAL OF REPRODUCTIVE MEDICINE 2012; 57:89-92. [PMID: 22324278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
BACKGROUND Ureteral injuries are known complications of urogynecologic surgery. Until now, ureteral reimplantation with laparotomy has been used in cases in which ureteral stenting of distal obstruction was unsuccessful. CASE We report a case of a 74-year-old woman with a recognized right ureteral injury after vaginal reconstructive surgery that failed ureteral stenting to relieve the obstruction and who presented with ureteral stricture and mild hydronephrosis 6 weeks postoperatively. Ureteroscopy with endoscopic balloon dilation reduced the stricture successfully. The patient remains asymptomatic, with normal renal sonogram, 6 months after the procedure. CONCLUSION Endoscopic balloon dilation is an effective technique that can be used for the management of ureteral strictures after urogynecologic surgery and avoids further surgical intervention.
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Cui N, Cao B, Liu YM, Liang LR, Gu L, Song SF, Guo P, Yin YD, Li F, Li BB, Su LL, Yang CX, Wang CL. OL-050 Clinical and economic impact of imipenem-resistant Acinetobacter baumannii in a teaching hospital in China. Int J Infect Dis 2010. [DOI: 10.1016/s1201-9712(10)60062-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Xiao W, Zhao C, Han F, Lu L, Wu S, Deng X, Lu T, Cui N. Concurrent Chemotherapy can Further Improve Clinical Outcome for Stage III Nasopharyngeal Carcinoma Patients Treated with IMRT in Endemic Area. Int J Radiat Oncol Biol Phys 2009. [DOI: 10.1016/j.ijrobp.2009.07.1492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Li Z, Cui N, Chen L. Treatment experience of subsequent complications after Roux-en-Y biliojejunostomy. ACTA ACUST UNITED AC 2009; 43:34-8. [PMID: 19420950 DOI: 10.1159/000216521] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2008] [Accepted: 02/10/2009] [Indexed: 11/19/2022]
Abstract
PURPOSE Roux-en-Y biliojejunostomy has been frequently used in the management of benign biliary disease. The aim of this study was to summarize one institute's experiences in prevention and management of subsequent complications of Roux-en-Y biliojejunostomy. METHODS A retrospective analysis was carried out for patients who underwent reoperation after Roux-en-Y biliojejunostomy from February 1990 through June 2004. Operation history, laboratory test data before the last operation, and images were collected. RESULTS Sixty-one patients, aged 36-60 years and with a 3.5-year average operation interval, were involved in the study. Anastomotic stricture (47, 80.3%), recurrent calculi (36, 60.7%), and biliary tract infection (all) were the most common complications after Roux-en-Y biliojejunostomy. Other complications (such as calculi of the intrahepatic duct or intrahepatic duct stricture, malformed or twisted jejunum loop, too long or too short proximal jejunum, disappearance of the normal form of anastomosis, and adhesion of the intestinal loop) were also detected by laparotomy. CONCLUSION Calculus, stricture, and infection arise as a result of each other. Lessening of the anastomotic stricture, fluent drainage of the distal jejunum below the anastomosis, and relieving pressure of gastrointestinal tract are pivotal in decreasing subsequent complications after Roux-en-Y biliojejunostomy.
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Wu S, Cui T, Zhao C, Pan J, Xu B, Tian Y, Cui N. A Randomized Controlled Multicenter Trial of Actovegin Against Acute Oral Mucositis Induced by Chemo-radiotherapy for Nasopharyngeal Carcinoma. Int J Radiat Oncol Biol Phys 2008. [DOI: 10.1016/j.ijrobp.2008.06.1237] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Shareef MM, Cui N, Burikhanov R, Gupta S, Satishkumar S, Shajahan S, Mohiuddin M, Rangnekar VM, Ahmed MM. Role of tumor necrosis factor-alpha and TRAIL in high-dose radiation-induced bystander signaling in lung adenocarcinoma. Cancer Res 2008; 67:11811-20. [PMID: 18089811 DOI: 10.1158/0008-5472.can-07-0722] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In the present study, ionizing radiation (IR)-induced bystander effects were investigated in two lung cancer cell lines. A549 cells were found to be more resistant to radiation-conditioned medium (RCM) obtained from A549 cells when compared with the H460 exposed to RCM procured from H460 cells. Significant release of tumor necrosis factor-alpha (TNF-alpha) was observed in A549 cells after IR/RCM exposure, and the survival was reversed with neutralizing antibody against TNF-alpha. In H460 cells, significant release of TNF-related apoptosis-inducing ligand (TRAIL), but not TNF-alpha, was observed in response to IR, RCM exposure, or RCM + 2Gy, and neutralizing antibody against TRAIL diminished clonogenic inhibition. Mechanistically, TNF-alpha present in RCM of A549 was found to mediate nuclear factor-kappaB (NF-kappaB) translocation to nucleus, whereas the soluble TRAIL present in RCM of H460 cells mobilized the nuclear translocation of PAR-4 (a proapoptotic protein). Analysis of IR-inducible early growth response-1 (EGR-1) function showed that EGR-1 was functional in A549 cells but not in H460 cells. A significant decrease in RCM-mediated apoptosis was observed in both A549 cells stably expressing small interfering RNA EGR-1 and EGR-1(-/-) mouse embryonic fibroblast cells. Thus, the high-dose IR-induced bystander responses in A549 may be dependent on the EGR-1 function and its target gene TNF-alpha. These findings show that the reduced bystander response in A549 cells is due to activation of NF-kappaB signaling by TNF-alpha, whereas enhanced response to IR-induced bystander signaling in H460 cells was due to release of TRAIL associated with nuclear translocation of PAR-4.
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Zhao C, Lu L, Han F, Huang S, Lin C, Deng X, Lu T, Cui N. 2394. Int J Radiat Oncol Biol Phys 2006. [DOI: 10.1016/j.ijrobp.2006.07.804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Zhao C, Lu L, Han F, Huang S, Lin C, Deng X, Lu T, Cui N. Preliminary Results of Intensity Modulated Radiation Therapy Alone for 122 Patients with Untreated Nasopharyngeal Carcinoma. Int J Radiat Oncol Biol Phys 2005. [DOI: 10.1016/j.ijrobp.2005.07.652] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Chen M, Chen Y, Bao Y, Xian C, Liu G, Zhang L, Xu G, Deng X, Lu T, Oian J, Cui N. Neoadjuvant chemotherapy followed by late-course accelerated hyperfractionated radiation therapy for locally advanced non-small cell lung cancer: The long term results of a phase I/II clinical trial. Int J Radiat Oncol Biol Phys 2004. [DOI: 10.1016/j.ijrobp.2004.07.485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Lu T, Cui N, Luo W, Zhao C, Wu S, Liu X, Chen Y, Xie F, Chen M, Hu W, Cao X, Xia Y. Retrospective analysis of 934 primary nasopharyngeal carcinoma (NPC) patients treated with conventional external beam radiotherapy alone. Int J Radiat Oncol Biol Phys 2004. [DOI: 10.1016/j.ijrobp.2004.07.451] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Cui N, Wu J, Xu H, Wang R, Rojas A, Piao H, Mao J, Abdulkadir L, Li L, Jiang C. A threonine residue (Thr71) at the intracellular end of the M1 helix plays a critical role in the gating of Kir6.2 channels by intracellular ATP and protons. J Membr Biol 2003; 192:111-22. [PMID: 12682799 DOI: 10.1007/s00232-002-1069-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2002] [Indexed: 10/27/2022]
Abstract
ATP-sensitive K+ (K(ATP)) channels are known to be gated by several intracellular molecules, but the gating mechanisms remain unclear. To understand the relationship of channel gating to ligand binding, we studied Kir6.2 channel gating by ATP and protons, which inhibit and activate the channel, respectively. We have previously shown that a threonine residue (Thr71) is critical for the pH sensitivity of Kir6.2 channel. If this site is involved in channel gating rather than ligand binding, it should affect channel gating by both ATP and proton. To test this hypothesis we performed a mutation analysis. Site-specific mutations of Thr71 to a bulky residue reduced the ATP sensitivity by >100-fold and eliminated the pH sensitivity. Single-channel activity of these mutants was stabilized at the open state with no detectable rundown. Mutations to a small amino acid had little effect on the ATP and pH sensitivities. Mutations to intermediate amino acids reduced but did not abolish the ATP and pH sensitivities. Hydrophobicity is not critical, as both polar and nonpolar amino acids are found in each group. Mutation to a positively charged lysine markedly exacerbated the pH- but not ATP-sensitivity, whereas mutation to glutamate moderately reduced ATP and pH sensitivities. These results indicate that the residue mass is critical for Kir6.2 channel gating, a mass that should be below 120 daltons with no charge. The existence of such a site as Thr71 involved in channel gating by both ATP and proton suggests that channel gating in the K(ATP) channel likely is separate from ligand binding.
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Xiang L, Zhao C, Han F, Huang Y, Deng X, Huang S, Zeng Z, Lin C, Cui N. Initial experience of using intensity modulated radiation therapy (IMRT) for recurrent nasopharyngeal carcinoma. Int J Radiat Oncol Biol Phys 2002. [DOI: 10.1016/s0360-3016(02)03355-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Cui N, Ma H, Luo J, Chiovelli S. Use of scanning reference electrode technique for characterizing pitting and general corrosion of carbon steel in neutral media. Electrochem commun 2001. [DOI: 10.1016/s1388-2481(01)00251-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Jiang C, Xu H, Cui N, Wu J. An alternative approach to the identification of respiratory central chemoreceptors in the brainstem. RESPIRATION PHYSIOLOGY 2001; 129:141-57. [PMID: 11738651 DOI: 10.1016/s0034-5687(01)00301-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Central chemoreceptors (CCRs) play a crucial role in autonomic respiration. Although a variety of brainstem neurons are CO(2) sensitive, it remains to know which of them are the CCRs. In this article, we discuss a potential alternative approach that may allow an access to the CCRs. This approach is based on identification of specific molecules that are CO(2) or pH sensitive, exist in brainstem neurons, and regulate cellular excitability. Their molecular identity may provide another measure in addition to the electrophysiologic criteria to indicate the CCRs. The inward rectifier K(+) channels (Kir) seem to be some of the CO(2) sensing molecules, as they regulate membrane potential and cell excitability and are pH sensitive. Among homomeric Kirs, we have found that even the most sensitive Kir1.1 and Kir2.3 have pK approximately 6.8, suggesting that they may not be capable of detecting hypocapnia. We have studied their biophysical properties, and identified a number of amino acid residues and molecular motifs critical for the CO(2) sensing. By comparing all Kirs using the motifs, we found the same amino acid sequence in Kir5.1, and demonstrated the pH sensitivity in heteromeric Kir4.1 and Kir5.1 channels to be pK approximately 7.4. In current clamp, we show evidence that the Kir4.1-Kir5.1 can detect P(CO(2)) changes in either hypercapnic or hypocapnic direction. Our in-situ hybridization studies have indicated that they are coexpressed in brainstem cardio-respiratory nuclei. Thus, it is likely that the heteromeric Kir4.1-Kir5.1 contributes to the CO(2)/pH sensitivity in these neurons. We believe that this line of research intended to identify CO(2) sensing molecules is an important addition to current studies on the CCRs.
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Cui N, Giwa LR, Xu H, Rojas A, Abdulkadir L, Jiang C. Modulation of the heteromeric Kir4.1-Kir5.1 channels by P(CO(2)) at physiological levels. J Cell Physiol 2001; 189:229-36. [PMID: 11598908 DOI: 10.1002/jcp.10021] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Several inward rectifier K(+) (Kir) channels are pH-sensitive, making them potential candidates for CO(2) chemoreception in cells. However, there is no evidence showing that Kir channels change their activity at near physiological level of P(CO(2)), as most previous studies were done using high concentrations of CO(2). It is known that the heteromeric Kir4.1-Kir5.1 channels are highly sensitive to intracellular protons with pKa value right at the physiological pH level. Such a pKa value may allow these channels to regulate membrane potentials with modest changes in P(CO(2)). To test this hypothesis, we studied the Kir4.1-Kir5.1 currents expressed in Xenopus oocytes and membrane potentials in the presence and absence of bicarbonate. Evident inhibition of these currents (by approximately 5%) was seen with P(CO(2)) as low as 8 torr. Higher P(CO(2)) levels (23-60 torr) produced stronger inhibitions (by 30-40%). The inhibitions led to graded depolarizations (5-45 mV with P(CO(2)) 8-60 torr). Similar effects were observed in the presence of 24 mM bicarbonate and 5% CO(2). Indeed, the Kir4.1-Kir5.1 currents were enhanced with 3% CO(2) and suppressed with 8% CO(2) in voltage clamp, resulting in hyper- (-9 mV) and depolarization (16 mV) in current clamp, respectively. With physiological concentration of extracellular K(+), the Kir4.1-Kir5.1 channels conduct substantial outward currents that were similarly inhibited by CO(2) as their inward rectifying currents. These results therefore indicate that the heteromeric Kir4.1-Kir5.1 channels are modulated by a modest change in P(CO(2)) levels. Such a modulation alters cellular excitability, and enables the cell to detect hypercapnia and hypocapnia in the presence of bicarbonate.
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