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Müller A, Ni Z, Hessler N, Wesarg F, Müller FA, Kralisch D, Fischer D. The Biopolymer Bacterial Nanocellulose as Drug Delivery System: Investigation of Drug Loading and Release using the Model Protein Albumin. J Pharm Sci 2013. [DOI: 10.1002/jps.23385] [Citation(s) in RCA: 140] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Ni Z, Bahl N, Gunraj C, Mazzella F, Chen R. 1.115 DECREASED MOTOR CORTICAL INHIBITION AND INCREASED FACILITATION IN PARKINSON'S DISEASE. Parkinsonism Relat Disord 2012. [DOI: 10.1016/s1353-8020(11)70229-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Ni Z, Wenjun Y, Sifeng C, Yongwen Q. Endothelial enriched microRNAs regulate angiotensin II-induced endothelial inflammation and migration. BRITISH HEART JOURNAL 2011. [DOI: 10.1136/heartjnl-2011-300867.133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Anderson O, Afolayan JO, Ni Z, Bates T. Surgical vs general practitioner assessment: diagnostic accuracy in 2-week-wait colorectal cancer referrals. Colorectal Dis 2011; 13:e212-5. [PMID: 21689308 DOI: 10.1111/j.1463-1318.2011.02617.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
AIM It has been recommended that patients with suspected colorectal cancer should proceed straight to an endoscopic test to increase speed of diagnosis, using only the information in the general practitioner's referral letter. This study aims to establish whether the diagnostic accuracy of the first surgical outpatient assessment is significantly greater than the general practitioner's assessment and if so by what means. METHOD Demographic variables, symptoms and signs were collected from the first surgical outpatient assessment letters and the general practitioners' referral letters in 2-week-wait colorectal cancer referrals made between 2002 and 2005. Multiple logistic regression models derived from both the surgeons' and the general practitioners' letters were compared with receiver operator characteristic curves. RESULTS Variables were collected from 978 2-week-wait colorectal cancer referrals. The median age was 69 years (range 19-98) and the male to female ratio was 1:2. Seventy-eight referrals were diagnosed with colorectal cancer. Surgeons' models demonstrated significantly greater diagnostic accuracy than general practitioners' models (area under the curve, 0.84 vs 0.73; P < 0.003). General practitioners' letters contained significantly less information than surgeons' letters (P < 0.001), but correcting for this did not account for the difference in diagnostic accuracy. The single variable that accounted for the difference in diagnostic accuracy was examination of the rectum by rigid sigmoidoscopy. CONCLUSION Rigid sigmoidoscopy significantly improves the diagnostic accuracy of clinical assessment in patients with suspected colorectal cancer. If rigid sigmoidoscopy were omitted in a straight-to-test pathway, some patients would be denied the opportunity for immediate diagnosis.
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Seiler S, Cremers B, Ege P, Fehrenz M, Hornof F, Jeken J, Kersting S, Rebling NM, Steimle C, Rogacev KS, Scheller B, Bohm M, Fliser D, Heine GH, Nagler EVT, Webster AC, Vanholder R, Zoccali C, Nagler EVT, Webster AC, Vanholder R, Zoccali C, Chinnappa S, Mooney A, El Nahas M, Tan LB, Lucisano G, Bova F, Presta P, Caglioti C, Caglioti A, Fuiano G, Ikeda A, Konta T, Takasaki S, Mashima Y, Kubota I, Nakamura S, Kokubo Y, Makino H, Takata H, Fujii T, Yoshihara F, Horio T, Kawano Y, Badulescu M, Capusa C, Stancu S, Blaga V, Ilyes A, Anghel C, Mircescu G, Tolkacheva V, Villevalde S, Tyukhmenev E, Kobalava Z, Shalyagin Y, Shvetsov M, Nagaytseva S, Lukshina L, Shilov E, Fusaro M, Tripepi G, Crepaldi G, Maggi S, D'Angelo A, Naso A, Plebani M, Vajente N, Giannini S, Calo L, Miozzo D, Cristofaro R, Gallieni M, Feriozzi S, Torras J, Cibulla M, Nicholls K, Sunder-Plassmann G, West M, Pavlikova E, Villevalde S, Kobalava Z, Moiseev V, Yen CT, Huang CH, Wang MC, Daher E, Silva Junior G, Vieira AP, Couto Bem A, Fiqueiredo Filho A, Lopes Filho A, Guedes A, Eloy Costa C, Holanda de Souza J, Liborio A, Daniel R, Nitsch D, Harper L, EUVAS Group, Little M, Khatami SMR, Mahmoodian M, Zare E, Pashang M, Mc Carroll F, Cooke B, O'Kane M, Moles K, Garrett P, Lindsay J, Yu TM, Chen CH, Wu MJ, Cheng CH, Chuang YW, Shu KH, Cole JC, Oberdhan D, Cheng R, Urwongse J, Krasa H, Czerwiec F, Chapman A, Perrone R, Moranne O, Fafin C, Favre G, Mougel S, Vido A, Seitz B, Dahan P, Albano L, Esnult V, Rama M, Gayathri P, Leelavathi DA, Ravindra PA, Sundaram V, Nageshwar PR, Presta P, Piraina V, Talarico R, Esposito G, Colombo A, Lucisano G, Caglioti C, Mazza G, Cirillo E, Quattrone S, Fuiano G, Marron B, Chen N, Shi H, Ma X, Zhang J, Mao P, He L, Yu J, Ding X, Jiang G, Gu Y, Zhang W, Wang N, Mei C, Ni Z, Tzanno C, Stein G, Nisihara F, Rocha J, Clesca P, Uezima C, Langham H, Tomlin M, Coyne E, Hope W, Bebb C, Johnson C, Byrne C, Li Y, Zhang W, Ren H, Wang W, Shi H, Li X, Chen X, Wu X, Chen N, Canver B, Colak T, Can S, Karakayali H, Bansal V, Davis R, Litinas E, Hoppensteadt D, Thethi I, Fareed J. General & clinical epidemiology CKD 1-5 (1). Clin Kidney J 2011. [DOI: 10.1093/ndtplus/4.s2.48] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Hallstrand TS, Lai Y, Ni Z, Oslund RC, Henderson WR, Gelb MH, Wenzel SE. Relationship between levels of secreted phospholipase A₂ groups IIA and X in the airways and asthma severity. Clin Exp Allergy 2011; 41:801-10. [PMID: 21255140 PMCID: PMC3093436 DOI: 10.1111/j.1365-2222.2010.03676.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Background Secreted phospholipase A(2) (sPLA(2) ) may be important mediators of asthma, but the specific sPLA(2) s involved in asthma are not known. Objective To evaluate sPLA(2) group IIA, V, and X proteins (sPLA(2) -IIA, sPLA(2) -V, and sPLA(2) -X) in bronchoalveolar lavage (BAL) fluid, BAL cells, and airway epithelial cells of subjects with and without asthma, and examine the relationship between the levels of specific sPLA(2) enzymes and airway inflammation, asthma severity, and lung function. Methods The expression of sPLA(2) -IIA, sPLA(2) -V, and sPLA(2) -X in BAL cells and epithelial brushings was assessed by qPCR. The levels of these sPLA(2) proteins and sPLA(2) activity with and without group II and group X-specific inhibitors were measured in BAL fluid from 18 controls and 39 asthmatics. Results The airway epithelium expressed sPLA(2) -X at higher levels than either sPLA(2) -IIA or sPLA(2) -V, whereas BAL cells expressed sPLA(2) -IIA and sPLA(2) -X at similar levels. The majority of sPLA(2) activity in BAL fluid was attributed to either sPLA(2) -IIA or sPLA(2) -X. After 10-fold concentration of BAL fluid, the levels of sPLA(2) -X normalized to total protein were increased in asthma and were associated with lung function, the concentration of induced sputum neutrophils, and prostaglandin E(2) . The levels of sPLA(2) -IIA were elevated in asthma when normalized to total protein, but were not related to lung function, markers of airway inflammation or eicosanoid formation. Conclusions and Clinical Relevance These data indicate that sPLA(2) -IIA and sPLA(2) -X are the major sPLA(2) s in human airways, and suggest a link between the levels of sPLA(2) -X in the airways and several features of asthma.
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Zhu M, Li Y, Xia Q, Wang S, Qiu Y, Che M, Dai H, Qian J, Ni Z, Axelsson J, Yan Y. Strong impact of acute kidney injury on survival after liver transplantation. Transplant Proc 2011; 42:3634-8. [PMID: 21094830 DOI: 10.1016/j.transproceed.2010.08.059] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Revised: 06/03/2010] [Accepted: 08/26/2010] [Indexed: 01/17/2023]
Abstract
Acute kidney injury (AKI) is a major complication in orthotopic liver transplantation (OLT). In an evaluation of Acute Kidney Injury Network (AKIN) criteria in liver transplanted patients, we retrospectively analyzed the usefulness of these criteria to predict survival of 193 consecutive patients at a single center who underwent primary OLT for clinical parameters and peak AKI. Postoperative AKI according to AKIN occurred in 60.1% of the patients, namely, stages 1, 2, and 3 in 30%, 13% and 17.1% respectively. Using multivariate logistic regression, AKIN stage 1 and 2 AKI were independently associated with the pre-OLT Model for End-Stage Liver Disease (MELD) score and age, while stage 3 AKI was independently associated with MELD and Acute Physiology and Chronic Health Evaluation (APACHE) II scores. The 28-day and 1-year mortality post-OLT of AKI patients were 15.5% and 25.9% respectively compared with 0% and 3.9% among non-AKI patients (P < .05 for both). The survival rates of non-AKI and stages 1, 2, and 3 AKI subjects were 96%, 85.5%, 84%, and 45.3%, respectively. Cox regression analysis showed independent risk factors for mortality during the first year after transplantation to include post-OLT AKI (12.1; P < .05), post-OLT infection (HR 4.7; P < .01), pre-OLT hypertension (HR 4.4; P < .01) hazard ratio [HR] and post-OLT APACHE II ≥10 (HR 3.6; P < .05). We concluded that AKI as defined by the AKIN criteria is a major complication of OLT linked to a poor outcomes. It remains to be evaluated whether aggressive perioperative therapy to prevent AKI can improve survival among OLT patients.
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Nelson AJ, Hoque T, Gunraj C, Ni Z, Chen R. Impaired interhemispheric inhibition in writer's cramp. Neurology 2010; 75:441-7. [PMID: 20679637 DOI: 10.1212/wnl.0b013e3181ebdda0] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVES Reduced cortical inhibition is a feature of focal hand dystonia and this likely contributes to excessive muscle contractions. Inhibition from the opposite hemisphere, known as interhemispheric inhibition (IHI), was studied bidirectionally in 7 right-handed patients with writer's cramp (WC) and age-matched healthy controls in a cross-sectional physiologic study. METHODS IHI was measured with paired transcranial magnetic stimulation with the conditioning stimulus applied to the motor cortex and the test stimulus applied to the contralateral motor cortex. Surface EMG was measured in right and left first dorsal interosseous muscles during rest, and while holding a pen between the thumb and index finger at 20% maximum voluntary contraction with the right dystonia-affected hand. The time course and magnitude of IHI was studied at interstimulus intervals of 6, 8, 10, 12, 30, 40, and 50 msec between the conditioning stimulus and test stimulus. RESULTS In WC at rest, IHI was significantly reduced in the dystonia-affected right hand (IHI from right to left motor cortex) at both short (SIHI, 10-12 msec) and long (LIHI, 30-40 msec) intervals compared to the unaffected hand. Compared to controls, SIHI and LIHI were reduced in the dystonia-affected hand only. There was no difference in IHI between controls and WC during the task of holding a pen. CONCLUSIONS In WC, both SIHI and LIHI are reduced in the dystonia-affected hand compared to the unaffected hand and to healthy controls. Impaired IHI may contribute to excessive muscle contraction in WC.
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Yun T, Ni Z, Liu G, Yu B, Chen L, Huang J, Zhang Y, Chen J. Generation of infectious and pathogenic duck hepatitis virus type 1 from cloned full-length cDNA. Virus Res 2010; 147:159-65. [DOI: 10.1016/j.virusres.2009.10.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2009] [Revised: 10/09/2009] [Accepted: 10/17/2009] [Indexed: 11/17/2022]
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Lin X, Lin A, Ni Z, Yao Q, Zhang W, Yan Y, Fang W, Gu A, Axelsson J, Qian J. Daily peritoneal ultrafiltration predicts patient and technique survival in anuric peritoneal dialysis patients. Nephrol Dial Transplant 2010; 25:2322-7. [DOI: 10.1093/ndt/gfq001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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Kuriakose R, Saha U, Castillo G, Udupa K, Ni Z, Gunraj C, Mazzella F, Hamani C, Lang AE, Moro E, Lozano AM, Hodaie M, Chen R. The Nature and Time Course of Cortical Activation Following Subthalamic Stimulation in Parkinson's Disease. Cereb Cortex 2009; 20:1926-36. [DOI: 10.1093/cercor/bhp269] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
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Ni Z, Gunraj C, Nelson AJ, Yeh IJ, Castillo G, Hoque T, Chen R. Two Phases of Interhemispheric Inhibition between Motor Related Cortical Areas and the Primary Motor Cortex in Human. Cereb Cortex 2008; 19:1654-65. [DOI: 10.1093/cercor/bhn201] [Citation(s) in RCA: 161] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Fang W, Qian J, Lin A, Rowaie F, Ni Z, Yao Q, Bargman JM, Oreopoulos DG. Comparison of peritoneal dialysis practice patterns and outcomes between a Canadian and a Chinese centre. Nephrol Dial Transplant 2008; 23:4021-8. [DOI: 10.1093/ndt/gfn372] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Ni Z, Gunraj C, Chen R. Two phases of interhemispheric inhibition between motor related cortical areas and the primary motor cortex in human. Brain Stimul 2008. [DOI: 10.1016/j.brs.2008.06.234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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Ni Z, Anastakis D, Gunraj C, Chen R. Reversal of cortical plasticity in human primary motor cortex following thumb reconstruction. Brain Stimul 2008. [DOI: 10.1016/j.brs.2008.06.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Yeom J, Oh I, Field C, Radadia A, Ni Z, Bae B, Han J, Masel R, Shannon M. Enhanced toxic gas detection using a MEMS preconcentrator coated with the metal organic framework absorber. ACTA ACUST UNITED AC 2008. [DOI: 10.1109/memsys.2008.4443635] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Vaziri ND, Bai Y, Ni Z, Quiroz Y, Pandian R, Rodriguez-Iturbe B. Intra-renal angiotensin II/AT1 receptor, oxidative stress, inflammation, and progressive injury in renal mass reduction. J Pharmacol Exp Ther 2007; 323:85-93. [PMID: 17636006 DOI: 10.1124/jpet.107.123638] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Significant reduction of renal mass triggers a chain of events that result in glomerular hypertension/hyperfiltration, proteinuria, glomerulosclerosis, tubulointerstitial injury, and end-stage renal disease. These events are mediated by a constellation of hemodynamic, oxidative, and inflammatory reactions that are, in part, driven by local AT1 receptor (AT1r) activation by angiotensin II (Ang II). Here we explored the effects of 5/6 nephrectomy with and without AT1r blockade (losartan for 8 weeks) on AT1r and AT2r and Ang II-positive cell count, pathways involved in oxidative stress and inflammation [NAD(P)H oxidase, nuclear factor kappaB (NFkappaB), 12-lipooxygenase, cyclooxygenase (COX)-1, COX-2, monocyte chemoattractant protein (MCP)-1, plasminogen activator inhibitor (PAI)-1, renal T cell, and macrophage infiltration] as well as renal function and structure. The untreated group exhibited hypertension, deterioration of renal function and structure, reduced or unchanged plasma renin activity, aldosterone concentration, marked up-regulations of AT1r (250%), Ang II-expressing cell count (>20-fold), NAD(P)H oxidase subunits (gp91(phox,) p22(phox), and P47(phox); 20-40%), COX-2 (250%), 12-lipooxygenase (100%), MCP-1 (400%), and PAI-1 (>20-fold), activation of NFkappaB, and interstitial infiltrations of T cells and macrophages in the remnant kidneys. AT1r blockade attenuated the biochemical and histological abnormalities, prevented hypertension, and decelerated deterioration of renal function and structure. Thus, the study demonstrated a link between up-regulation of Ang II/AT1r system and oxidative stress, inflammation, hypertension, and progression of renal disease in rats with renal mass reduction.
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Li J, Tian H, Li Q, Wang N, Wu T, Liu Y, Ni Z, Yu H, Liang J, Luo R, Li Y, Huang L. Improvement of insulin sensitivity and beta-cell function by nateglinide and repaglinide in type 2 diabetic patients - a randomized controlled double-blind and double-dummy multicentre clinical trial. Diabetes Obes Metab 2007; 9:558-65. [PMID: 17587398 DOI: 10.1111/j.1463-1326.2006.00638.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIM To evaluate the efficacy of nateglinide vs. repaglinide in blood glucose (BG) control and the effect on insulin resistance and beta-Cell function in patients with type 2 diabetes. METHODS A randomized controlled double-blind and double-dummy multicentre clinical trial was conducted. A total of 230 Chinese patients with type 2 diabetes were enrolled in five clinical centres. The patients were divided randomly into group A [repaglinide 1.0 mg three times daily (t.i.d.), n = 115] or group B (nateglinide 90 mg t.i.d., n = 115). At baseline and end of the 12-week clinical trial, standard mixed meal tolerance tests were performed. RESULTS A total of 223 patients (96.9%) completed the trial. There was no significant difference between repaglinide and nateglinide groups in the effects of reducing fasting blood glucose (FBG), 30-, 60- and 120-min BG during 12 weeks (p > 0.05). At week 12, no significant difference was shown between the two groups in BG or haemoglobin A(1c) (HbA(1c)) (p > 0.05). However, the effect on HbA(1c) in repaglinide group was stronger than that in nateglinide group (p < 0.05). After 12-week treatment, area under the curve (AUC) of BG decreased (p < 0.05), and AUC of insulin and C-peptide (CP) increased in both groups (p < 0.05). The effects of nateglinide on AUC of BG, insulin and CP were similar to that of repaglinide (p > 0.05). There was no significant difference between the two groups in AUC of BG, insulin or CP in week 12 (p > 0.05). Furthermore, homeostasis model assessment of insulin resistance (HOMA-IR) and beta-cell function indexes measured by HOMA-beta, DeltaI(30)/DeltaG(30) and (DeltaI(30)/DeltaG(30))/HOMA-IR were improved significantly in both groups during 12 weeks (p < 0.05). The effects of improving HOMA-IR and beta-cell function indexes in nateglinide group were comparable with that of repaglinide group (p > 0.05). CONCLUSIONS The efficacy of repaglinide and nateglinide in FBG, postprandial glucose excursion and early-phase insulin secretion is similar. But the effect of repaglinide 1.0 mg t.i.d. on HbA(1c) is stronger than that of nateglinide 90 mg t.i.d.. This trial had shown that nateglinide and repaglinide could comparably improve insulin sensitivity and beta-cell function.
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Li Z, Rodríguez-Iturbe B, Ni Z, Shahkarami A, Sepassi L, Vaziri ND. Effect of hereditary obesity on renal expressions of NO synthase, caveolin-1, AKt, guanylate cyclase, and calmodulin. Kidney Int 2006; 68:2766-72. [PMID: 16316351 DOI: 10.1111/j.1523-1755.2005.00747.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Obesity has emerged as a major cause of diabetes, cardiovascular disease, and renal insufficiency worldwide. Obese Zucker rats exhibit hyperphagia, obesity, insulin resistance, hyperlipidemia, and glomerulosclerosis and are frequently used as a model to study hereditary form of metabolic syndrome. Nitric oxide plays a major role in preservation of renal function and structure. The present study was designed to test the hypothesis that renal disease in this model may be associated with down-regulation of endothelial (eNOS) and neuromal NO synthases (nNOS) in the kidney. The study further sought to explore expressions of caveolin-1, phospho AKt, and calmodulin, which regulate activities of constituitive NOS isoforms, as well as soluble guanylate cyclase (sGC), which is involved in NO signaling. METHODS Twenty-two-week-old male obese and lean Zucker rats were studied. Body weight, serum lipids, urine albumin excretion, and renal tissue abundance of the above proteins were determined. RESULTS Serum glucose and arterial pressure were unchanged, whereas urinary NO metabolite (NO(chi)) excretion and renal tissue nitrotyrosine abundance were markedly reduced (denoting depressed NO production) in the obese versus lean Zucker rats. This was accompanied by significant glomerulosclerosis, tubulointerstitial damage, renal immune cell infiltration, marked down-regulations of renal tissue eNOS and nNOS, mild reduction of caveolin-1, and unchanged calmodulin, phospho-AKt, and sGC. CONCLUSION Hereditary obesity can result in down-regulations of kidney eNOS and nNOS, marked reduction of NO production, and glomerulosclerosis prior to the onset of frank diabetes and hypertension.
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Pham A, Ni Z, Sepassi L, Vaziri N. Effect of Renal Mass Reduction on Adenosine Triphosphate Binding Cassette A-1 and Scavenger Receptors Sr-A1 and Sr-B1 in the Kidney. J Investig Med 2006. [DOI: 10.1177/108155890605401s230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Pham AH, Ni Z, Sepassi L, Vaziri ND. 347 EFFECT OF RENAL MASS REDUCTION ON ADENOSINE TRIPHOSPHATE BINDING CASSETTE A-1 AND SCAVENGER RECEPTORS SR-A1 AND SR-B1 IN THE KIDNEY. J Investig Med 2006. [DOI: 10.2310/6650.2005.x0004.346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Vaziri ND, Ni Z. Expression of NOX-I, gp91phox, p47phox and P67phox in the aorta segments above and below coarctation. Biochim Biophys Acta Gen Subj 2005; 1723:321-7. [PMID: 15814300 DOI: 10.1016/j.bbagen.2005.03.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2005] [Revised: 02/28/2005] [Accepted: 03/03/2005] [Indexed: 10/25/2022]
Abstract
Aorta coarctation results in hypertension (HTN) in the arterial tree proximal to stenosis and, as such, provides an ideal model to discern the effects of different levels of blood pressure on the vascular tissue in the same animal. Compelling evidence has emerged supporting the role of oxidative stress as a cause of HTN. However, whether or not HTN (independent of the circulating humoral factors) can cause oxidative stress is less certain. NAD(P)H oxidase isoforms are the main source of reactive oxygen species (ROS) in the vascular tissues. We therefore compared the expressions of NOX-I, gp91phox and the regulatory subunits of the enzyme in the aorta segments residing above and below coarctation in rats with abdominal aorta banding. Rats were studied 4 weeks after aorta banding above the renal arteries or sham operation. Subunits of NAD(P)H oxidase and its NOX-I isoform as well as endothelial NO synthase (eNOS) and nitrotyrosine (footprint of NO oxidation by superoxide) were measured in the aorta segments above and below coarctation. The gp91phox, p47phox, and p67phox subunits of NAD(P)H oxidase, NOX-I isoform, eNOS and nitrotyrosine were markedly increased in the aorta segment above coarctation (hypertensive zone), but were virtually unchanged in the segment below coarctation. Since, excepting blood pressure, all other conditions were constant, the upregulation of NAD(P)H oxidase isoforms and the increased NO oxidation in the aorta segment above, but not below, coarctation prove that HTN, per se, independent of circulating mediators can cause oxidative/nitrosative stress in the arterial wall. These observations suggest that HTN control may represent a specific form of antioxidant therapy for hypertensive disorders.
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Vaziri ND, Ding Y, Ni Z, Barton CH. Bradykinin Down-Regulates, Whereas Arginine Analogs Up-Regulates, Endothelial Nitric-Oxide Synthase Expression in Coronary Endothelial Cells. J Pharmacol Exp Ther 2005; 313:121-6. [PMID: 15640399 DOI: 10.1124/jpet.104.076497] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Bradykinin (BK) is an endogenous vasoactive peptide that promotes vasodilation by stimulating the release of nitric oxide (NO) from endothelial cells via activation of endothelial NO synthase (eNOS). Although the role of BK in modulation of eNOS activity is well understood, its possible effect on eNOS expression remains uncertain. Several studies have demonstrated negative feedback regulation of eNOS by NO. Therefore, we hypothesized that sustained stimulation with BK may down-regulate eNOS expression in endothelial cells. Human coronary endothelial cells were incubated for 24 h with either BK alone or BK plus BK receptor type 1 or type 2 blockers. NO production and eNOS abundance (Western analysis) were determined. In separate experiments, cells were incubated with either an NOS inhibitor alone or in combination with BK. Incubation with BK caused a concentration-dependent rise in NO production and a dose-dependent decline in eNOS protein expression. These effects were abrogated by BK-2 blockade but unaffected by BK-1 blockade. In contrast, NOS inhibitors lowered NO production and raised eNOS abundance in a dose-dependent fashion. The effects of BK on NO production and eNOS expression were abrogated by the NOS inhibitor. Thus, sustained activation of eNOS by BK results in a compensatory down-regulation of eNOS, whereas its sustained inhibition leads to a compensatory up-regulation of eNOS. The observed modulations of eNOS expression are mediated by NO and represent an adaptive physiologic response.
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Abstract
Melasma (or chloasma) is a common disorder of cutaneous hyperpigmentation predominantly affecting sun-exposed areas in women. The pathogenesis of melasma is not fully understood and treatments are frequently disappointing and often associated with side effects. Pycnogenol is a standardized extract of the bark of the French maritime pine (Pinus pinaster), a well-known, potent antioxidant. Studies in vitro show that Pycnogenol is several times more powerful than vitamin E and vitamin C. In addition, it recycles vitamin C, regenerates vitamin E and increases the endogenous antioxidant enzyme system. Pycnogenol protects against ultraviolet (UV) radiation. Therefore its efficacy in the treatment of melasma was investigated. Thirty women with melasma completed a 30-day clinical trial in which they took one 25 mg tablet of Pycnogenol with meals three times daily, i.e. 75 mg Pycnogenol per day. These patients were evaluated clinically by parameters such as the melasma area index, pigmentary intensity index and by routine blood and urine tests. After a 30-day treatment, the average melasma area of the patients decreased by 25.86 +/- 20.39 mm(2) (p < 0.001) and the average pigmentary intensity decreased by 0.47 +/- 0.51 unit (p < 0.001). The general effective rate was 80%. No side effect was observed. The results of the blood and urine test parameters at baseline and at day 30 were within the normal range. Moreover, several other associated symptoms such as fatigue, constipation, pains in the body and anxiety were also improved. To conclude, Pycnogenol was shown to be therapeutically effective and safe in patients suffering from melasma.
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Tian D, Ma H, Feng Z, Xia Y, Le XC, Ni Z, Allen J, Collins B, Schreinemachers D, Mumford JL. Analyses of micronuclei in exfoliated epithelial cells from individuals chronically exposed to arsenic via drinking water in inner Mongolia, China. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2001; 64:473-484. [PMID: 11732698 DOI: 10.1080/152873901753215939] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The groundwater in Bayingnormen (Ba Men), located in Central West Inner Mongolia, China, is naturally contaminated with arsenic at concentrations ranging from 50 microg/L to 1.8 mg/L. Various adverse health effects in this region, including cancer, have been linked to arsenic exposure via drinking water. A pilot study was undertaken to evaluate frequencies of micronuclei (MN), as measures of chromosomal alterations, in multiple exfoliated epithelial cell types from residents of Ba Men chronically exposed to arsenic via drinking water. Buccal mucosal cells, airway epithelial cells in sputum, and bladder urothelial cells were collected from 19 residents exposed to high levels of arsenic in drinking water (527.5 +/- 24 microg/l), and from 13 control residents exposed to relatively low levels of arsenic in drinking water (4.4 +/- microg/L). Analytical results from these individuals revealed that MN frequencies in the high-exposure group were significantly elevated to 3.4-fold over control levels for buccal and sputum cells, and to 2.7-fold over control for bladder cells (increases in MN frequency significant at p < .001 for buccal cells; p < .01 for sputum cells; p < .05 for bladder cells). When smokers were excluded from high-exposure and control groups the effects of arsenic were observed to be greater, although only in buccal and sputum cells; approximately 6-fold increases in MN frequency occurred in these tissues. The results indicate that residents of Ba Men chronically exposed to high levels of arsenic in drinking water reveal evidence of genotoxicity in multiple epithelial cell types; higher levels of induced MN were observed in buccal and sputum cells than in bladder cells.
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Abstract
BACKGROUND Abdominal aortic coarctation above the renal arteries leads to severe hypertension (HTN) above the stenotic site. We have recently shown marked up-regulations of endothelial nitric oxide synthase (eNOS) in heart and thoracic aorta and of neuronal NOS (nNOS) in the brain of rats with severe aortic coarctation above the renal arteries. We hypothesize that the presence of severe regional HTN in the face of marked up-regulation of NO system may be partly due to enhanced NO inactivation by reactive oxygen species (ROS) leading to functional NO deficiency. METHODS Tissue nitrotyrosine (which is the footprint of NO interaction with ROS) was determined by Western blot in sham-operated control and aortic-banded (above renal arteries) rats three weeks postoperatively. Intra-arterial pressure and tissue nitrotyrosine (Western blot) were measured. RESULTS The banded group showed a marked rise in arterial pressure measured directly through a carotid cannula (203 +/- 9 vs. 131 +/- 2 mm Hg, P < 0.01). Compared with the sham-operated controls, the banded animals exhibited significant increases in nitrotyrosine abundance in the heart, brain, and the aorta segment above the stricture. In contrast, nitrotyrosine abundance was unchanged in the abdominal aorta segment below the stricture wherein blood pressure was not elevated. CONCLUSION Coarctation-induced HTN is associated with increased nitrotyrosine abundance in all tissues exposed to high arterial pressure, denoting enhanced ROS-mediated inactivation and sequestration of NO in these sites. This can, in part, account for severe regional HTN in this model. The normality of nitrotyrosine abundance in the abdominal aorta wherein blood pressure is not elevated points to the role of baromechanical factors as opposed to circulating humoral factors that were necessarily similar in both segments.
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Vaziri ND, Ding Y, Ni Z. Compensatory up-regulation of nitric-oxide synthase isoforms in lead-induced hypertension; reversal by a superoxide dismutase-mimetic drug. J Pharmacol Exp Ther 2001; 298:679-85. [PMID: 11454931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023] Open
Abstract
Chronic exposure to low levels of lead causes hypertension (HTN) that is, in part, due to increased inactivation of nitric oxide (NO) by reactive oxygen species (ROS). The latter results in functional NO deficiency and compensatory up-regulation of NO synthase (NOS). We have previously shown evidence for increased hydroxyl radical (*OH) activity in rats with lead-induced HTN. Since in the biological systems *OH is primarily derived from superoxide (O2*) we hypothesize that lead-induced oxidative stress and HTN must be due to increased O2* production and as such could be ameliorated by administration of a cell-permeable O2* scavenger. We, therefore, studied the effects of the superoxide dismutase (SOD)-mimetic drug tempol (15 mmol/kg/day i.p. x 2 weeks) and placebo in lead-exposed (given lead acetate, 100 ppm in the drinking water for 12 weeks) and normal control rats. Lead exposure resulted in a marked elevation of blood pressure, a significant reduction in urinary NO metabolites (NO(chi)) excretion, and up-regulations of endothelial and inducible NOS abundance in the kidney, aorta, and heart and of neuronal NOS in the cerebral cortex and brain stem. Administration of tempol ameliorated HTN, increased urinary NO(chi) excretion, and reversed the compensatory up-regulation of NOS isoforms in rats with lead-induced HTN. These abnormalities recurred within 2 wk after discontinuation of tempol. In contrast to the lead-exposed rats, the normal control rats showed no change in either blood pressure, urinary NO(chi) excretion, or tissue NOS expression in response to either administration or discontinuation of tempol. Thus, the study supports the presence of increased O2* activity and its role in the pathogenesis of HTN and altered NO metabolism in lead-exposed animals.
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Ni Z, Gao D, Bouali-Benazzouz R, Benabid AL, Benazzouz A. Effect of microiontophoretic application of dopamine on subthalamic nucleus neuronal activity in normal rats and in rats with unilateral lesion of the nigrostriatal pathway. Eur J Neurosci 2001; 14:373-81. [PMID: 11553287 DOI: 10.1046/j.0953-816x.2001.01644.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The subthalamic nucleus (STN) receives dopamine inputs from the substantia nigra but their implication in the pathophysiology of parkinsonism is still debated. Extracellular microrecordings were used to study the effect of microiontophoretic injection of dopamine and the D1 receptor agonist SKF 38393 on the activity of STN neurons in normal and 6-hydroxydopamine-lesioned rats under urethane anaesthesia. Dopamine and SKF induced an increase in the firing rate of the majority of STN neurons in both normal and 6-OHDA rats. In rats with 6-OHDA lesions, the percentage of firing rate increase did not differ from that of controls. When GABA, glutamate and dopamine were all applied to the same individual STN neurons, GABA induced an inhibitory effect and glutamate and dopamine caused an excitatory effect in both groups. This excitatory response was suppressed by the application of GABA. Systemic administration of apomorphine provoked a decrease in the firing rate of STN neurons in rats with 6-OHDA lesions. These results show that dopamine exerts an excitatory influence on STN neurons, suggesting that the inhibitory effect induced by the systemic injection of apomorphine is due to the GABAergic inputs from the globus pallidus as predicted by the current model of basal ganglia organization. In addition, we show that dopamine, GABA and glutamate can act on the same STN neuron and that GABA can reverse the excitatory effect of dopamine and glutamate, suggesting the predominant influence of GABAergic inputs to the subthalamic nucleus.
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Ni Z, Bouali-Benazzouz R, Gao D, Benabid AL, Benazzouz A. Intrasubthalamic injection of 6-hydroxydopamine induces changes in the firing rate and pattern of subthalamic nucleus neurons in the rat. Synapse 2001; 40:145-53. [PMID: 11252026 DOI: 10.1002/syn.1036] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The subthalamic nucleus (STN) receives dopaminergic projections from the substantia nigra pars compacta (SNc). To investigate the role of direct and indirect dopaminergic influences on STN neurons, the spontaneous activity was studied in four groups of animals: normal rats, rats with intrasubthalamic or intranigral injection of 6-hydroxydopamine (6-OHDA), and sham STN injection rats by using extracellular recordings 4 weeks postsurgery. After intrasubthalamic injection of 6-OHDA, the mean firing rate significantly decreased (7.29 +/- 0.39 spikes/sec, P < 0.01 vs. 11.13 +/- 0.59 spikes/sec in normal or 11.26 +/- 0.57 spikes/sec in sham group), and the percentage of STN neurons discharging regularly decreased significantly (81%, P < 0.05 vs. 90% in normal group or P < 0.01 vs. 92% in sham group) and that of bursty cells increased (19%, P < 0.05 vs. 10%; in normal group or P < 0.01 vs. 8% in sham group). In the group of rats with SNc lesion, the firing rate of subthalamic neurons did not show a significant difference (11.61 +/- 0.81 spikes/sec) compared with normal group. However, the firing pattern was dramatically changed: 74% of cells exhibited bursty pattern and only 26% of cells discharged regularly or slightly irregularly. Immunohistochemical results showed that intrasubthalamic injection of 6-OHDA induced a marked degeneration of dopaminergic cells in the lateral part of the ipsilateral SNc, whereas 6-OHDA injection into the SNc induced a total in situ lesion of dopamine cells. These results suggest that the SNc exerts an excitatory influence on STN neurons and that the loss of this dopaminergic projection could, at least partially, account for the changes in the firing pattern of STN neurons in the 6-OHDA rat model of parkinsonism.
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Yan X, Ni Z. [Speciation of metals and metalloids in biomolecules by hyphenated techniques]. GUANG PU XUE YU GUANG PU FEN XI = GUANG PU 2001; 21:129-138. [PMID: 12947604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
This paper introduces briefly the analytical methods recently published in the literature on the speciation of arsenic, selenium and cadmium in biological samples using hyphenated techniques, HPLC-ICP-MS, HPLC-ES-MS/MS, and CE-ES-MS/MS. The coupling SEC-ICP-MS is the most popular technique for the first screening of unknown sample in view of the presence of macro molecular species of element. But due to its insufficient resolution, complementary chromatographic separations have to be carried out in order to guarantee the purity of the signal. CZE-ICP-MS is a powerful tool in trace metal speciation. In case standards and reference materials are not available, ES-MS/MS is the best technique in the characterization of metal complexes. During analysis care should be taken to avoid contamination of the sample and break-up of the original metal-protein bond during the separation process. Due to lack of standards and reference materials, the application of hyphenated technique has been looking for new species rather than determining a known compound. The difficult problems are whether a signal produced by a detector belongs to a particular compound and the identification of this compound.
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Barton CH, Ni Z, Vaziri ND. Effect of severe aortic banding above the renal arteries on nitric oxide synthase isotype expression. Kidney Int 2001; 59:654-61. [PMID: 11168947 DOI: 10.1046/j.1523-1755.2001.059002654.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Severe aortic stenosis above the renal arteries leads to a reduction in renal perfusion, increased renin secretion, and elevation of arterial blood pressure above the stenotic site. Nitric oxide (NO) plays an important role in regulation of renal and systemic vascular resistance, renal blood flow, and Na(+) handling. Abdominal aortic banding provides an excellent model for simultaneous testing of the effects of increased and decreased pressure, flow, and shear stress in the same animal. METHODS We studied protein expressions of endothelial NO synthase (eNOS), inducible NOS (iNOS), and neuroneal NOS (nNOS) isotypes in the renal cortex, renal medulla, heart, brain, and aorta segments above and below the stenosis site three weeks after abdominal aortic banding above the renal arteries. The results were compared with those obtained in the sham-operated controls. NOS isotype proteins were measured by Western blot. RESULTS Compared with the control group, the banded group showed significant up-regulations of eNOS, iNOS, and nNOS in renal cortex and medulla. Likewise, heart eNOS, brain nNOS, and thoracic aorta eNOS proteins were significantly increased in the banded group. However, eNOS and iNOS expressions were unchanged in the aorta segment below the stenotic site. Likewise, iNOS expression in the heart and thoracic aorta remained unchanged in the banded animals. No significant difference was found in creatinine clearance or urinary protein excretion between the two groups. CONCLUSIONS These findings clearly demonstrate the up-regulatory action of increased pressure on eNOS expression in the thoracic aorta and heart and of nNOS expression in the brain. These data further show up-regulation of all NOS isotypes in the kidney, which must have helped to mitigate the associated hypoperfusion.
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Ni Z, Vaziri ND. Effect of salt loading on nitric oxide synthase expression in normotensive rats. Am J Hypertens 2001; 14:155-63. [PMID: 11243307 DOI: 10.1016/s0895-7061(00)01234-6] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
Elevation of arterial blood pressure (BP) with high salt intake in Dahl salt-sensitive rats is associated and perhaps, in part, due to downregulation of renal and vascular production of nitric oxide (NO) and nitric oxide synthase (NOS) expressions. Several recent studies have revealed a significant increase in BP in Sprague-Dawley rats on high salt intake. Given the apparent salt sensitivity of Sprague-Dawley rats, we hypothesized that chronic high salt intake may affect NO system in these rats in a manner resembling that reported in salt-sensitive (not salt-resistant) Dahl rats. The effects of a high salt diet (chow containing 8% NaCl) of 48-h or 3-week duration was studied on immunodetectable endothelial (eNOS), inducible (iNOS), and neuronal (nNOS) NOS expressions of relevant organs in male Sprague-Dawley rats. The results were compared with those obtained in the control animals fed a regular no-added salt diet (0.2% NaCl). Consumption of a high salt diet for 3 weeks induced hypertension (HTN) (158 +/- 6 v 115 +/- 5 mm Hg, P < .01) and widespread downregulation of iNOS expression in renal cortex, renal medulla, aorta, and heart. Similarly, chronic salt loading resulted in marked downregulation of eNOS expression in renal cortex and aorta and lowered expressions of nNOS in the brain, renal cortex, and renal medulla. In comparison, short-term salt loading resulted in significant reduction of iNOS in the renal cortex and aorta and of eNOS in the aorta together with significant elevation of nNOS expression in renal medulla and brain. Thus, chronic consumption of a high salt diet resulted in moderate HTN in normotensive Sprague-Dawley rats. This was accompanied by widespread downregulation of various NOS isotypes that undoubtedly contributed to the development and maintenance of HTN in this model.
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Ke C, Ni Z, Wang YJ, Tang Y, Gu Y, Gao Z, Yang WL. Electrophoretic assembly of nanozeolites: zeolite coated fibers and hollow zeolite fibers. Chem Commun (Camb) 2001. [DOI: 10.1039/b010197o] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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84
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Ni Z, Jiao X, Gao S, Zhang R, Liu X. [Cloning and expression of Shiga-like toxin type II variant B gene of E. coli]. WEI SHENG WU XUE BAO = ACTA MICROBIOLOGICA SINICA 2000; 40:591-7. [PMID: 12549052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
A structure sequence and a DNA fragment including the signal peptide sequence and structure sequence of Shiga-like toxin II variant B subunit gene were amplified from E. coli strain O138 by PCR. After digested with restriction endonuclease EcoRI and BamHI, the two genes were orientally inserted into the polycloning site of expression vector pYA3334 (asd+) respectively. Recombinant plasmids pB0 and pB1 were constructed and amplified in E. coli X6212 (asd-). pB0 and pB1 were then introduced into avirulent Salmonella typhimurium vaccine strain X4550 (asd-) by serial transformation through intermediate strain X3730 (asd-) to construct recombinant SLT-IIvB strain. Results of nucleotide sequencing of the cloned fragments in pB0 and pB1 revealed that they were in correct ORF of SLT-IIvB. The results of SDS-PAGE and Western-blot showed that 7.6 kD protein of SLT-IIvB antigen was expressed at pretty high level in recombinant strain X4550(pB0). The results of mice immunization indicated X4550(pB0) could initiate the host to produce specific antibodies to SLT-IIvB and LPS-O antigen of X4550. So the recombinant strain X4550 (pB0) is worth considering as a candidate vaccine strain against porcine edema disease and Salmonella typhimurium infections.
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Vaziri ND, Ni Z, Oveisi F, Trnavsky-Hobbs DL. Effect of antioxidant therapy on blood pressure and NO synthase expression in hypertensive rats. Hypertension 2000; 36:957-64. [PMID: 11116107 DOI: 10.1161/01.hyp.36.6.957] [Citation(s) in RCA: 145] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Earlier studies have demonstrated evidence for increased reactive oxygen species, enhanced NO synthase (NOS) expression, and elevated NO production in spontaneously hypertensive rats (SHR). Given the negative-feedback regulation of NOS by NO, we hypothesized that enhanced NO inactivation by ROS may contribute to compensatory upregulation of NOS in SHR. The present study was designed to test this hypothesis. Eight-week-old male SHR and Wistar-Kyoto rats were treated for 3 weeks with either a placebo or the potent antioxidant, lazaroid (desmethyltirilazad, 10 mg. kg(-1). d(-1), by gastric gavage). Tail arterial blood pressure, urinary excretion of NO metabolites (ie, nitrate and nitrite), and immunodetectable NOS isotype proteins in the vascular, renal, cardiac, and cerebral tissues were measured. The placebo-treated SHR group showed a marked elevation of blood pressure and a significant upregulation of aorta, kidney, and cardiac tissue endothelial and inducible NOS (eNOS and iNOS, respectively) proteins and of brain and renal tissue neuronal NOS. Lazaroid therapy ameliorated hypertension and mitigated the upregulation of eNOS and iNOS in vascular, renal, and cardiac tissues but had limited effect on the expression of renal and brain neuronal NOS. In contrast, lazaroid therapy had no effect on blood pressure, urinary nitrate and nitrite excretion, or tissue NOS isotype expressions in the Wistar-Kyoto group. These findings support the role of oxidative stress in the genesis and/or maintenance of hypertension and compensatory upregulation of the expression of eNOS and iNOS in SHR.
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Ni Z, Bouali-Benazzouz R, Gao D, Benabid AL, Benazzouz A. Changes in the firing pattern of globus pallidus neurons after the degeneration of nigrostriatal pathway are mediated by the subthalamic nucleus in the rat. Eur J Neurosci 2000; 12:4338-44. [PMID: 11122344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Changes in the neuronal activity of globus pallidus (GP) have been shown in animal models of parkinsonism. In order to study the implication of the subthalamic nucleus (STN) in these changes, the effects of STN lesions alone or in combination with 6-hydroxydopamine (6-OHDA) -induced damage to the substantia nigra compacta (SNc) were examined in rats using electrophysiological recordings of GP cells. In normal rats, the firing rate was 22.1+/-1.4 spikes/s. The pattern was regular in 45%, irregular in 49% and bursty in 6% of the cases. In rats with STN lesions, the firing rate of GP units (20.15+/-1.25 spikes/s) did not differ from that of normal rats and only regular (46%) and irregular (54%) cells were found; a bursty pattern was not observed. 6-OHDA lesions of the SNc induced no change in the firing rate of GP neurons (21.5+/-1.4 spikes/s, P>0.05) but a significant decrease in the percentage of regular cells (27%, P<0.001), a significant increase in burst cells (21%, P<0.001) with no change in the percentage of irregular units (52%) were observed. In rats with combined SNc and STN lesions, the firing pattern did not change from that of normal rats. The present results show that STN lesions induced the disappearance of bursts in normal rats and normalization of firing pattern in the GP units of rats with 6-OHDA lesions suggesting that the STN plays an important role in the modulation of the pattern of activity of GP neurons which may account for the therapeutic effect of STN lesions in Parkinson's disease.
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Li W, Zhu Y, Yan X, Zhang Q, Li X, Ni Z, Shen Z, Yao H, Zhu J. [The prevention of primary liver cancer by selenium in high risk populations]. ZHONGHUA YU FANG YI XUE ZA ZHI [CHINESE JOURNAL OF PREVENTIVE MEDICINE] 2000; 34:336-8. [PMID: 11860943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
OBJECTIVE To study the preventive effects of selenium on primary liver cancer. METHODS After screening of blood samples in 18,000 males from 20 to 65 years-old in Qidong, Jiangsu province (a high risk area for liver cancer), 2,065 cases of HBsAg positive, AFP negative and normal liver function (normal ALT values) were found. The subjects were randomly divided into two groups, based on their residence areas; 1,112 subjects (experimental group) received one tablet of sodium selenite (0.5 mg Se) every day and 953 subjects (control group) received one placebo tablet every day. RESULTS During three years of intervention and follow up, the blood selenium concentration and glutathione peroxidase activity of the subjects in the experimental group were increased and had significant difference as compared with those of the control group (P < 0.01). At the same time, the prevalence rate of micronucleus cells in peripheral blood lymphocytes in the experimental group was significantly lower than that of the control group (P < 0.01), and the incidence of new liver cancer in the experimental group (3 057.55/10(6), 34 cases out of 1,112 subjects) was significantly lower than the control group (5 981.11/10(6); 57 cases out of 953 subjects) (P < 0.01). CONCLUSION The results confirms that selenium supplementation in general populations lived in high risk is effective in the prevention of liver cancer and the using of selenium tablets is simple and feasible.
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Liao Y, He F, Li A, Ni Z. Direct determination of platinum in urine by electrothermal atomic absorption spectrometry. AMERICAN CLINICAL LABORATORY 2000; 19:14-5. [PMID: 11317414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
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89
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Ni Z, Sun Q, Liu Z, Wu L, Wang X. Identification of a hybrid-specific expressed gene encoding novel RNA-binding protein in wheat seedling leaves using differential display of mRNA. MOLECULAR & GENERAL GENETICS : MGG 2000; 263:934-8. [PMID: 10954078 DOI: 10.1007/pl00008693] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
A hybrid-specific expressed cDNA fragment, designated as AG5, has been identified in wheat seedling leaves using differential mRNA display. AG5 contains an open reading frame (ORF) encoding 183 amino acid residues. Comparison with amino acid sequences in GenBank revealed that the AG5 protein is homologous to a group of Gly-rich proteins with consensus sequence-type RNA-binding domains (CS-RBD). Structural analysis showed that AG5 protein contains five motifs, including a consensus sequence-type RNA-binding domain near its N-terminus, arginine/aspartic acid repeats and a Gly-rich region in its center, a Cys-X2-Cys-X4-His-X4-Cys (CCHC) zinc finger motif in the Gly-rich region, and TrySer2ArgAsp2Arg repeats towards its C-terminus. Of all previously described RNA-binding proteins, only RZ-1 from tobacco has a similar structure to the AG5 protein, but RZ-1 lacks a TrySer2ArgAsp2Arg repeat motif, indicating that the two proteins may belong to a family of closely related proteins in plants. The possible role of AG5 and its relation to wheat heterosis are discussed.
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Zhou XJ, Laszik Z, Ni Z, Wang XQ, Brackett DJ, Lerner MR, Silva FG, Vaziri ND. Down-regulation of renal endothelial nitric oxide synthase expression in experimental glomerular thrombotic microangiopathy. J Transl Med 2000; 80:1079-87. [PMID: 10908153 DOI: 10.1038/labinvest.3780113] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Infection with certain strains of Escherichia coli and endotoxemia results in renal glomerular thrombotic microangiopathy (TMA) characterized by endothelial swelling and prominent glomerular microthrombus formation. Nitric oxide (NO) is an endogenous biologic modulator with diverse physiologic functions including vasodilation and inhibition of platelet adhesion and aggregation. NO is synthesized from conversion of L-arginine to L-citrulline by a family of NO synthases (NOS), which include constitutive and inducible isoforms. Indirect evidence supports the hypothesis that TMA is associated with depressed intrarenal NO production. However, the effect of TMA on renal tissue NOS expression has not been fully elucidated. We studied rats with TMA induced by iv bolus injection of high dose (20 mg/kg) E. coli endotoxin. Subgroups of six animals each were sacrificed before or at 30, 90, 180, 360, and 720 minutes after the administration of endotoxin. Renal histology and tissue expression of endothelial and inducible nitric oxide synthases (eNOS and iNOS) were examined. Additionally, we examined the effect of endotoxin on glomerular NO production, and eNOS and iNOS protein expression in vitro. Glomerular capillary thrombosis developed by 180 minutes after endotoxin administration in approximately half of the animals. The glomeruli without thrombotic lesions apparent by light microscopy disclosed early signs of TMA characterized by endothelial swelling, platelet accumulation/adhesion, and patchy fibrinogen deposition. These morphologic changes were associated with a marked reduction of renal tissue eNOS expression beyond 180 minutes after the endotoxin administration. The fall in eNOS expression was coupled with a significant rise in iNOS protein abundance, which was expressed largely by glomerular circulating neutrophils and endothelial cells, peritubular vascular endothelium, and collecting ducts of cortex and medulla. In vitro incubation of isolated glomeruli with endotoxin also resulted in a marked reduction in eNOS expression and a significant rise in iNOS content. Administration of E. coli endotoxin leads to a sustained fall in renal eNOS expression both in vivo and in vitro. The associated decline in intrarenal endothelial NO production/availability may result in renal vasoconstriction and a hypercoagulative state, which may contribute to the pathogenesis of endotoxin-induced TMA.
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91
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Ni Z, Liu Y, Keshava N, Zhou G, Whong W, Ong T. Analysis of K-ras and p53 mutations in mesotheliomas from humans and rats exposed to asbestos. Mutat Res 2000; 468:87-92. [PMID: 10863160 DOI: 10.1016/s1383-5718(00)00043-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Malignant mesothelioma is known to be associated with asbestos exposure. However, the mechanism of mesothelial carcinogenesis in relation to the activation of proto-oncogenes or inactivation of tumor suppressor genes remains unclear. In this study, the PCR-Primer Introduced Restriction Site (PCR-PIRS) assay was employed to examine mutations in the K-ras proto-oncogene in mesothelioma tissues from workers exposed to asbestos and from rats treated with asbestos. Mutations in exons 5-8 of the p53 tumor suppressor gene were determined by direct DNA sequence analysis. Results of the PCR-PIRS analysis revealed no mutations in codons 12, 13 or 61 of the K-ras gene in any of the 17 human or 22 rat mesothelioma tissue samples. These results were confirmed by direct DNA sequence analysis. No mutations were found in exons 5-8 of the p53 gene in any of the mesothelioma tissue samples analyzed. These results and the results reported by others indicate that the K-ras proto-oncogene and p53 tumor suppressor gene may not play a critical role in the induction of mesothelioma by asbestos either in humans or in rats.
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92
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Benazzouz A, Gao D, Ni Z, Benabid AL. High frequency stimulation of the STN influences the activity of dopamine neurons in the rat. Neuroreport 2000; 11:1593-6. [PMID: 10841382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
The effect of high frequency stimulation (HFS) of the subthalamic nucleus (STN) on the spontaneous activity of substantia nigra pars compacta (SNc) dopaminergic neurons was investigated in normal rats and in rats with globus pallidus (GP) lesions. In normal rats, the spontaneous activity of SNc neurons did not significantly differ from that of rats with GP lesions (4.2+/-2.2 versus 4.4+/-2.6 spikes/s). STN-HFS induced an increase of firing rate in the majority of tested cells in normal (76%) and GP-lesioned rats (73%) with an after-effect of 34.4+/-3.4 and 33.2+/-3.1 s, respectively. These results demonstrate that STN-HFS influences the activity of the SNc dopaminergic neurons by increasing their firing rate and that this increase of activity is independent of the globus pallidus.
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93
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Wang YJ, Tang Y, Ni Z, Hua WM, Yang WL, Wang XD, Tao WC, Gao Z. Synthesis of Macroporous Materials with Zeolitic Microporous Frameworks by Self-Assembly of Colloidal Zeolites. CHEM LETT 2000. [DOI: 10.1246/cl.2000.510] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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94
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Ni Z, Lou W, Leman ES, Gao AC. Inhibition of constitutively activated Stat3 signaling pathway suppresses growth of prostate cancer cells. Cancer Res 2000; 60:1225-8. [PMID: 10728680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Overexpression of interleukin 6, a downstream target of the GBX2 homeobox gene, has been linked to the progression of prostate cancer. The Janus kinase-signal transducers and activators of transcription signaling pathway transmits interleukin 6-mediated signals from cell surface receptors to the target genes in the nucleus and is critical in mediating cellular growth and differentiation. We demonstrate that cells derived from both rat and human prostate cancers have constitutively activated Stat3, with Stat3 activation being correlated with malignant potential. Blockade of activated Stat3 by ectopic expression of a dominant-negative Stat3 in human prostate cancer cells significantly suppresses their growth in vitro and their tumorigenicity in vivo. Furthermore, the Janus kinase inhibitor, tyrphostin AG490, inhibited the constitutive activation of Stat3 and suppressed the growth of human prostate cancer cells. These results indicate that activation of Stat3 signaling is essential in the progression of prostate cancer cells and suggest that targeting Stat3 signaling may yield a potential therapeutic intervention for prostate cancer.
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95
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Abstract
BACKGROUND Interleukin-6 (IL-6) is a pleiotropic cytokine that regulates growth and differentiation of various types of malignant tumors, including prostate carcinomas. The levels of IL-6 are elevated in sera of patients with metastatic prostate cancer. In this study, we evaluate the role of IL-6 in the growth regulation of prostate cancer cells. METHODS Expression of IL-6 and its receptors in human prostate cancer cells was measured by ELISA and RT-PCR. The effects of IL-6 on cell growth were evaluated by ectopically expressing IL-6 cDNA into IL-6-negative LNCaP human prostate cancer cells. Stat3 DNA binding activities were analyzed by electromobility shift assay and supershift assay. RESULTS Expression of IL-6 was detected in the androgen-insensitive prostate cancer cell lines (i.e. , TSU, PC3, and DU145), but not in the androgen-sensitive LNCaP cell line. IL-6 receptors, including both IL-6-specific receptor alpha chain and gp130 signal transducer, are expressed in all human prostate cancer cell lines (i.e., LNCaP, TSU, PC3, and DU145). Overexpression of IL-6 by ectopically expressing IL-6 into IL-6-negative LNCaP human prostate cancer cells significantly increased clonogenic ability and cell proliferation in vitro compared to the IL-6-negative parental LNCaP cells and the antisense controls. This growth stimulation by IL-6 was accompanied by activation of the Stat3 signaling transduction pathway. CONCLUSIONS IL-6 is an autocrine growth factor for LNCaP human prostate cancer cells; the effects of IL-6 on prostate cancer cell growth are mediated through the Janus kinase-signal transducers and activators of transcription (JAK-STAT) signaling pathway.
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96
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Ni Z, Zhang Q, Qian J, Wang L. Effect of Astragalin on matrix secretion and beta 1 integrin mRNA expression in human mesangial cells. Chin Med J (Engl) 1999; 112:1063-7. [PMID: 11721439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023] Open
Abstract
OBJECTIVE To investigate the effect of Astragalin on human renal mesangial cells. METHODS Cultured human mesangial cells were treated with Astragalin and Astragalin serum in different concentrations in the presence or absence of PDGF-BB, the proliferation and type IV collagen secretion of mesangial cells were measured by MTT assay and ELISA, and expression of beta 1 integrin gene was estimated by reverse transcription-polymerase chain reaction (RT-PCR) method, suspectively. RESULTS After 72 hours Astragalin or Astragalin serum treatment, the proliferation of mesangial cells induced by PDGF-BB was inhibited significantly in a dose-dependent manner compared with untreated controls (P < 0.05 and P < 0.01). After 24 hours of Astragalin or Astragalin serum treatment, the secretion of type IV collagen protein in presence of PDGF-BB was significantly decreased and beta 1 integrin mRNA level decreased significantly compared with untreated control (P < 0.05, P < 0.01). CONCLUSIONS Astragalin inhibits cell proliferation and matrix over-synthesis which might be mediated, at least, partly by decrease of beta 1 integrin gene over-expression. The study suggested that Astragalin might play a role in preventing the progression of chronic renal diseases.
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97
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Vaziri ND, Ding Y, Ni Z. Nitric oxide synthase expression in the course of lead-induced hypertension. Hypertension 1999; 34:558-62. [PMID: 10523326 DOI: 10.1161/01.hyp.34.4.558] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We recently showed elevated reactive oxygen species (ROS), reduced urinary excretion of NO metabolites (NOx), and increased NO sequestration as nitrotyrosine in various tissues in rats with lead-induced hypertension. This study was designed to discern whether the reduction in urinary NOx in lead-induced hypertension is, in part, due to depressed NO synthase (NOS) expression. Male Sprague-Dawley rats were randomly assigned to a lead-treated group (given lead acetate, 100 ppm, in drinking water and regular rat chow), a group given lead and vitamin E-fortified chow, or a normal control group given either regular food and water or vitamin E-fortified food for 12 weeks. Tail blood pressure, urinary NOx excretion, plasma malondialdehyde (MDA), and endothelial and inducible NOS (eNOS and iNOS) isotypes in the aorta and kidney were measured. The lead-treated group exhibited a rise in blood pressure and plasma MDA concentration, a fall in urinary NOx excretion, and a paradoxical rise in vascular and renal tissue eNOS and iNOS expression. Vitamin E supplementation ameliorated hypertension, lowered plasma MDA concentration, and raised urinary NOx excretion while significantly lowering vascular, but not renal, tissue eNOS and iNOS expression. Vitamin E supplementation had no effect on either blood pressure, plasma MDA, or NOS expression in the control group. The study also revealed significant inhibition of NOS enzymatic activity by lead in cell-free preparations. In conclusion, lead-induced hypertension in this model was associated with a compensatory upregulation of renal and vascular eNOS and iNOS expression. This is, in part, due to ROS-mediated NO inactivation, lead-associated inhibition of NOS activity, and perhaps stimulatory actions of increased shear stress associated with hypertension.
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98
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Ni Z, Oveisi F, Vaziri ND. Nitric oxide synthase isotype expression in salt-sensitive and salt-resistant Dahl rats. Hypertension 1999; 34:552-7. [PMID: 10523325 DOI: 10.1161/01.hyp.34.4.552] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Previous studies have suggested that salt-sensitive hypertension in humans and experimental animals may in part be due to dysregulation of the L-arginine/nitric oxide system. This study was conducted to determine the endothelial, inducible, and neuronal nitric oxide synthase expressions in the kidney, heart, aorta, and brain of salt-sensitive and salt-resistant Dahl rats. We studied salt-sensitive and salt-resistant Dahl rats maintained on high- (8%) and regular- (0.2%) salt diets for 3 weeks. Blood pressure was modestly elevated in both Dahl salt-sensitive and salt-resistant rats consuming regular diet and severely increased in sensitive but not resistant rats consuming the high-salt diet. The Dahl salt-sensitive animals showed a significant reduction in kidney, heart, and aorta inducible nitric oxide synthase protein abundance on the regular diet, with further reductions on the high-salt diet. In addition, the high-salt diet markedly downregulated endothelial nitric oxide synthase expression in the kidney and aorta but not in the heart of the Dahl salt-sensitive animals. The rise in blood pressure in the Dahl salt-sensitive rats on the high-salt diet was accompanied by a significant elevation of brain neuronal nitric oxide synthase protein. In contrast, salt-resistant animals showed no change in heart, kidney, and aorta endothelial or brain neuronal nitric oxide synthase and considerably less intense changes in inducible isotype than that seen in the salt-sensitive group in response to the high-salt diet. In conclusion, the study revealed a marked downregulation of inducible nitric oxide synthase in the Dahl salt-sensitive rats on the regular diet, with further reductions on the high-salt diet. Furthermore, Dahl salt-sensitive rats consuming the high-salt diet showed significant reductions of kidney and aorta endothelial nitric oxide synthase and an upregulation of brain neuronal nitric oxide synthase expression.
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Ni Z, Sun L, Zhou J. [Expression and characteristics of laryngeal carcinoma-associated antigen]. ZHONGHUA ZHONG LIU ZA ZHI [CHINESE JOURNAL OF ONCOLOGY] 1999; 21:205-7. [PMID: 11776837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
OBJECTIVE To study the characteristics of laryngeal carcinoma-associated antigen (LCAA) and its expression on laryngeal carcinoma tissue. METHODS The binding of a cocktail monoclonal antibodies Lc9, Lc11, Lc12 to human laryngeal squamous-cell carcinoma, laryngeal precancerous lesions and normal laryngeal mucosa was examined by immunohistochemical method. LCAA isolated and purified by gel-filtration, and chromotography from 3 laryngeal squamous-cell carcinomas. The reactivity of the purified antigen was determined after treatment with trypsin, NaIO4, methanol and heating. RESULTS The positive rate of LCAA expression in 90 cases of laryngeal carcinoma, 14 cases of precancerous lesions and in 10 cases of normal laryngeal mucosa was 97.7%, 50.0% and 0, respectively. LCAA was a glycoprotein, moderately heat stable. The purified antigen gave two bands of apparent molecular weights of 61,400 and 56,500 on SDS-PAGE and Western blot. CONCLUSION The results provide a basis for immunoimaging diagnosis and targeting chemotherapy for laryngeal cancer.
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Li X, Ni Z. [On the problems of fitting linear regression models for hierarchically structured data in medical research]. HUA XI YI KE DA XUE XUE BAO = JOURNAL OF WEST CHINA UNIVERSITY OF MEDICAL SCIENCES = HUAXI YIKE DAXUE XUEBAO 1999; 30:59-61. [PMID: 12205926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
There are a large number of the hierarchically structured data in the field of medical sciences, which have been analyzed usually by conventional linear regression models. The objective of this paper is to explore the problems and the relationship of parameter estimates of the three common linear regression models in fitting the hierarchically structured date, and the correction of the precision of parameter estimates. It is shown that the estimate of parameter and it's precision of linear regression models is related to the variation of independent variable between and within level 2 units, and the difference of residual estimates is associated with the difference of parameter estimates. The three common linear regression models are all inappropriate for the hierarchically structured data, but the standard error of the level 1 combined model can be corrected by variance inflation factor in conditions.
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