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Codispoti LA, Friederich GE, Packard TT, Glover HE, Kelly PJ, Spinrad RW, Barber RT, Elkins JW, Ward BB, Lipschultz F, Lostaunau N. High Nitrite Levels off Northern Peru: A Signal of Instability in the Marine Denitrification Rate. Science 2010; 233:1200-2. [PMID: 17756872 DOI: 10.1126/science.233.4769.1200] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
During February and March 1985, nitrite levels along the northern (approximately 7 degrees to 10 degrees S) Peruvian coast were unusually high. These accumulations occurred in oxygen-deficient waters, suggesting intensified denitrification. In a shallow offshore nitrite maximum, concentrations were as high as 23 micromoles per liter (a record high). Causes for the unusual conditions may include a cold anomaly that followed the 1982-83 El Niño. The removal of combined nitrogen (approximately 3 to 10 trillion grams of nitrogen per year) within zones of new or enhanced denitrification observed between 7 degrees to 16 degrees S suggests a significant increase in oceanic denitrification.
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Kelly PJ, Weiss SE, Sher DJ, Perez-Atayde AR, Dal Cin P, Choueiri TK. Sunitinib-induced pseudoprogression after whole-brain radiotherapy for metastatic renal cell carcinoma. J Clin Oncol 2010; 28:e433-5. [PMID: 20547999 DOI: 10.1200/jco.2009.26.8193] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Giovannetti G, Khomyakov PA, Brocks G, Karpan VM, van den Brink J, Kelly PJ. Doping graphene with metal contacts. PHYSICAL REVIEW LETTERS 2008; 101:026803. [PMID: 18764212 DOI: 10.1103/physrevlett.101.026803] [Citation(s) in RCA: 778] [Impact Index Per Article: 48.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2008] [Indexed: 05/25/2023]
Abstract
Making devices with graphene necessarily involves making contacts with metals. We use density functional theory to study how graphene is doped by adsorption on metal substrates and find that weak bonding on Al, Ag, Cu, Au, and Pt, while preserving its unique electronic structure, can still shift the Fermi level with respect to the conical point by approximately 0.5 eV. At equilibrium separations, the crossover from p-type to n-type doping occurs for a metal work function of approximately 5.4 eV, a value much larger than the graphene work function of 4.5 eV. The numerical results for the Fermi level shift in graphene are described very well by a simple analytical model which characterizes the metal solely in terms of its work function, greatly extending their applicability.
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Karpan VM, Giovannetti G, Khomyakov PA, Talanana M, Starikov AA, Zwierzycki M, van den Brink J, Brocks G, Kelly PJ. Graphite and graphene as perfect spin filters. PHYSICAL REVIEW LETTERS 2007; 99:176602. [PMID: 17995355 DOI: 10.1103/physrevlett.99.176602] [Citation(s) in RCA: 146] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2007] [Indexed: 05/07/2023]
Abstract
Based upon the observations (i) that their in-plane lattice constants match almost perfectly and (ii) that their electronic structures overlap in reciprocal space for one spin direction only, we predict perfect spin filtering for interfaces between graphite and (111) fcc or (0001) hcp Ni or Co. The spin filtering is quite insensitive to roughness and disorder. The formation of a chemical bond between graphite and the open d-shell transition metals that might complicate or even prevent spin injection into a single graphene sheet can be simply prevented by dusting Ni or Co with one or a few monolayers of Cu while still preserving the ideal spin-injection property.
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Hatami M, Bauer GEW, Zhang Q, Kelly PJ. Thermal spin-transfer torque in magnetoelectronic devices. PHYSICAL REVIEW LETTERS 2007; 99:066603. [PMID: 17930848 DOI: 10.1103/physrevlett.99.066603] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2006] [Indexed: 05/25/2023]
Abstract
We predict that the magnetization direction of a ferromagnet can be reversed by the spin-transfer torque accompanying spin-polarized thermoelectric heat currents. We illustrate the concept by applying a finite-element theory of thermoelectric transport in disordered magnetoelectronic circuits and devices to metallic spin valves. When thermalization is not complete, a spin heat accumulation vector is found in the normal-metal spacer, i.e., a directional imbalance in the temperature of majority and minority spins.
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Dear GJ, Patel N, Kelly PJ, Webber L, Yung M. TopCount coupled to ultra-performance liquid chromatography for the profiling of radiolabeled drug metabolites in complex biological samples. J Chromatogr B Analyt Technol Biomed Life Sci 2006; 844:96-103. [PMID: 16931187 DOI: 10.1016/j.jchromb.2006.07.041] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2006] [Revised: 06/21/2006] [Accepted: 07/02/2006] [Indexed: 10/24/2022]
Abstract
The recent commercial availability of small particle packed columns (<2microm) and associated instrumentation capable of withstanding the high pressures of such columns, has lead to an increase in the application of so called ultra-performance liquid chromatography (UPLC). It has recently been shown that the improved efficiency, resolution and peak capacity of these columns, when coupled to mass spectrometry, provides particular benefit for the identification of drug metabolites in complex biological samples. In this work, the ability of TopCount, a microplate scintillation counter, to act as a suitable radiodetection system for ultra-performance liquid chromatography methods is tested. TopCount, has innumerable benefits over more traditional on-line radioactivity flow detection methods, when dealing with the narrow peak widths and small peak volumes associated with the enhanced efficiency of sub-2microm columns. The system is tested for robustness and sensitivity, and then used to undertake successful metabolite profiling of actual samples, and the data compared to traditional HPLC with on-line radioactivity flow detector.
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Ning M, Furie KL, Koroshetz WJ, Lee H, Barron M, Lederer M, Wang X, Zhu M, Sorensen AG, Lo EH, Kelly PJ. Association between tPA therapy and raised early matrix metalloproteinase-9 in acute stroke. Neurology 2006; 66:1550-5. [PMID: 16717217 DOI: 10.1212/01.wnl.0000216133.98416.b4] [Citation(s) in RCA: 138] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Matrix metalloproteinase-9 (MMP9) is expressed in acute ischemic stroke and up-regulated by tissue plasminogen activator (tPA) in animal models. The authors investigated plasma MMP9 and its endogenous inhibitor, tissue inhibitor of metalloproteinase (TIMP1), in tPA-treated and -untreated stroke patients. METHODS Nonstroke control subjects and consecutive ischemic stroke patients presenting within 8 hours of onset were enrolled. Blood was sampled within 8 hours and at 24 hours, 2 to 5 days and 4 to 6 weeks. MMP9 and TIMP1 were analyzed by ELISA and gel zymography. RESULTS Fifty-two cases (26 tPA treated, 26 tPA untreated) and 27 nonstroke control subjects were enrolled. Hyperacute MMP9 was elevated in tPA-treated vs tPA-untreated patients (medians 43 vs 28 ng/mL; p = 0.01). tPA therapy independently predicted hyperacute MMP9 after adjustment for stroke severity, volume, and hemorrhagic transformation (p = 0.01). There was a trend toward lower hyperacute TIMP1 levels in tPA-treated vs tPA-untreated patients (p = 0.06). Hyperacute MMP9 was correlated to poor 3-month modified Rankin Scale outcome (r = 0.58, p = 0.0005). CONCLUSION Tissue plasminogen activator independently predicted plasma matrix metalloproteinase-9 (MMP9) in the first 8 hours after human ischemic stroke. As MMP9 may be an important mediator of hemorrhagic transformation, alternative thrombolytic agents or therapeutic MMP9 inhibition may increase the safety profile of acute stroke thrombolysis.
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Xu PX, Xia K, Zwierzycki M, Talanana M, Kelly PJ. Orientation-dependent transparency of metallic interfaces. PHYSICAL REVIEW LETTERS 2006; 96:176602. [PMID: 16712319 DOI: 10.1103/physrevlett.96.176602] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2005] [Indexed: 05/09/2023]
Abstract
As devices are reduced in size, interfaces start to dominate electrical transport, making it essential to be able to describe reliably how they transmit and reflect electrons. For a number of nearly perfectly lattice-matched materials, we calculate from first principles the dependence of the interface transparency on the crystal orientation. Quite remarkably, the largest anisotropy is predicted for interfaces between the prototype free-electron materials silver and aluminum, for which a massive factor of 2 difference between (111) and (001) interfaces is found.
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Kelly PJ, Midwinter A, Rolain JM, Raoult D. Polymerase chain reaction (PCR) survey for rickettsias and bartonellas in ticks from New Zealand. N Z Vet J 2006; 53:468-9. [PMID: 16317451 DOI: 10.1080/00480169.2005.36595] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Audronis M, Kelly PJ, Leyland A, Matthews A. A TEM study of the structure of magnetron sputtered chromium diboride coatings. ACTA ACUST UNITED AC 2006. [DOI: 10.1088/1742-6596/26/1/086] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Geller SE, Adams MG, Kelly PJ, Kodkany BS, Derman RJ. Postpartum hemorrhage in resource-poor settings. Int J Gynaecol Obstet 2006; 92:202-11. [PMID: 16427056 DOI: 10.1016/j.ijgo.2005.12.009] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2005] [Revised: 11/30/2005] [Accepted: 12/07/2005] [Indexed: 11/26/2022]
Abstract
Despite the strong interest of international health agencies, worldwide maternal mortality has not declined substantially over the past 10 years. Postpartum hemorrhage (PPH) is the most common cause of maternal death across the world, responsible for more than 25% of deaths annually. Although effective tools for prevention and treatment of PPH are available, most are not feasible or practical for use in the developing world where many births still occur at home with untrained birth attendants. Application of many available clinical solutions in rural areas would necessitate substantial changes in government infrastructure and in local culture and customs surrounding pregnancy and childbirth. Before treatment can be administered, prompt and accurate diagnosis must be made, which requires training and appropriate blood measurement tools. After diagnosis, appropriate interventions that can be applied in remote settings are needed. Many uterotonics known to be effective in reducing PPH in tertiary care settings may not be useful in community settings because they require refrigeration and/or skilled administration. Moreover, rapid transfer to a higher level of care must be available, a challenge in many settings because of distance and lack of transportation. In light of these barriers, low-technological replacements for treatments commonly applied in the developed-world must be utilized. Community education, improvements to emergency care systems, training for birth attendants, misoprostol, and Uniject have shown promise as potential solutions. In the short term, it is expedient to capitalize on practical opportunities that utilize the existing strengths and resources in each community or region in order to implement appropriate solutions to save the lives of women during childbirth.
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Mahan S, Kelly PJ, Mahan SM. A preliminary study to evaluate the immune responses induced by immunization of dogs with inactivated Ehrlichia canis organisms. Onderstepoort J Vet Res 2005; 72:119-28. [PMID: 16137129 DOI: 10.4102/ojvr.v72i2.207] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Ehrlichia canis is an intracellular pathogen that causes canine monocytic ehrlichiosis. Although the role of antibody responses cannot be discounted, control of this intracellular pathogen is expected to be by cell mediated immune responses. The immune responses in dogs immunized with inactivated E. canis organisms in combination with Quil A were evaluated. Immunization provoked strong humoral and cellular immune responses, which were demonstrable by Western blotting and lymphocyte proliferation assays. By Western blotting antibodies to several immunodominant E. canis proteins were detected in serum from immunized dogs and antibody titres increased after each immunization. The complement of immunogenic proteins recognized by the antisera were similar to those recognized in serum from infected dogs. Upon challenge with live E. canis, rapid anamnestic humoral responses were detected in the serum of immunized dogs and primary antibody responses were detected in the serum from control dogs. Following immunization, a lymphocyte proliferative response (cellular immunity) was detected in peripheral blood mononuclear cells (PBMNs) of immunized dogs upon stimulation with E. canis antigens. These responses were absent from non-immunized control dogs until after infection with live E. canis, when antigen specific-lymphocyte proliferation responses were also detected in the PBMNs of the control dogs. It can be thus concluded that immunization against canine monocytic ehrlichiosis may be feasible. However, the immunization regimen needs to be optimized and a detailed investigation needs to be done to determine if this regimen can prevent development of acute and chronic disease.
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Kelly PJ, Musuka G, Eoghin GN, Tebje-Kelly JBU, Carter S. Serosurvey for canine distemper virus exposure in dogs in communal lands in Zimbabwe. J S Afr Vet Assoc 2005; 76:104-6. [PMID: 16108530 DOI: 10.4102/jsava.v76i2.406] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Sera from 173 apparently healthy, unvaccinated dogs from 4 widely separated communal lands in Zimbabwe were tested by ELISA for antibodies against canine distemper virus. Overall, 82% were positive with high prevalences found in each communal land. The highest seroprevalence was in dogs between 1 and 2 years of age (91%; 49/54). These results show dogs in the communal lands of Zimbabwe are commonly exposed to canine distemper virus and that a substantial number survive infection. The role that the virus might play in the high mortality rate of the dog population on communal land warrants further investigation.
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Kelly PJ, Eoghain GN, Raoult D. Antibodies reactive with Bartonella henselae and Ehrlichia canis in dogs from the communal lands of Zimbabwe. J S Afr Vet Assoc 2005; 75:116-20. [PMID: 15628802 DOI: 10.4102/jsava.v75i3.465] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
The prevalences of antibodies against Bartonella henselae and Ehrlichia canis were determined in sera from 228 dogs in 5 communal lands of Zimbabwe, areas where traditional subsistence agro-pastoralism is practised. The sera were collected from apparently healthy dogs during routine rabies vaccination programmes and tested with indirect fluorescent antibody assays using B. henselae (Houston-I) and E. canis (Oklahoma) as antigens. We found reactive antibodies (> or =1:80) against B. henselae in 14% of the dogs tested. Seropositive animals were found in Bikita (41%; 17/42), Omay (13%; 6/48), Chinamora (5%; 2/38) and Matusadona (15%; 7/48). No seropositive dogs were found in Chiredzi (0%; 0/52). Antibodies reactive with E. canis (> or =1:80) were found in 34% of the dogs tested, from Bikita (88%; 37/42), Chiredzi (31%; 16/52), Omay (17%; 8/48), Chinamora (26%; 10/38) and Matusadona (15%; 7/48). Our survey shows dogs in the communal lands of Zimbabwe are frequently exposed to E. canis and B. henselae or closely related species. Further studies are indicated to determine the pathogenicity of the organisms infecting these dogs and their clinical significance.
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Abstract
The cat flea, Ctenocephalides felis, is the recognised vector of Bartonella henselae, B. clarridgeiae and Rickettsia felis. Although these Gram-negative bacteria were only described in the last decade, they are already known to cause a variety of diseases in people, particularly children and the immunosuppressed. Such diseases include cat-scratch disease, bacillary angiomatosis, endocarditis, bacteraemia, encephalopathy, neuroretinitis, osteomyelitis and peliosis hepatis. Although most infections in cats and dogs appear to be subclinical, recent studies have provided growing evidence that the bartonellas can also cause serious problems in pets, including hepatitis, endocarditis, central nervous system (CNS) signs, lymphadenopathy, uveitis, cataracts and reproductive failure. In 2004, DNA of B. henselae, B. clarridgeiae and R. felis was demonstrated in cat fleas from New Zealand and pets and their owners in the country are thus at risk of infection. While flea control programmes have traditionally been advocated by veterinarians to prevent pruritus and tapeworms in pets, they should now also be recommended to prevent infections with the new flea-borne bacterial pathogens. To raise awareness of the organisms amongst veterinarians and animal health workers, this review describes: the biology of the organisms; clinical and laboratory features of infections in cats, dogs and people; diagnosis; and possible treatments and control of infections with these organisms.
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Greenfield JR, Samaras K, Jenkins AB, Kelly PJ, Spector TD, Campbell LV. Do gene-environment interactions influence fasting plasma lipids? A study of twins. Eur J Clin Invest 2004; 34:590-8. [PMID: 15379757 DOI: 10.1111/j.1365-2362.2004.01389.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND The aims of this study were to determine the influence of smoking, alcohol consumption, physical activity and hormone replacement therapy (HRT) on lipids, independently of genetic factors, and to detect whether gene-environment interactions influence these associations. MATERIALS AND METHODS Fasting plasma total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides, apolipoproteins AI and B and lipoprotein(a) were measured in 685 female twins (96 monozygotic, 230 dizygotic pairs and 33 singletons). RESULTS Smokers had higher triglyceride and lower HDL cholesterol levels than never-smokers (P < 0.001). After controlling for genetic influences, smoking accounted for 0.35 mmol L(-1) and 0.22 mmol L(-1) differences in triglyceride and HDL cholesterol levels, respectively (P < 0.005), remaining significant after excluding alcohol-discordant twin pairs. In a gene-environment interaction analysis, the association between smoking and triglycerides was exaggerated in subjects at high genetic risk of hypertriglyceridaemia (interaction P=0.04). All levels of alcohol consumption were associated with higher HDL cholesterol levels than abstinence, but only moderate alcohol consumers had lower LDL cholesterol and triglyceride levels. In monozygotic twins concordant for smoking, an alcohol intake > 10 units week(-1) accounted for a 0.32 mmol L(-1) difference in LDL cholesterol, independently of genetic effects (P=0.04). In postmenopausal women, those using HRT had 0.54 mmol L(-1) lower LDL cholesterol and 0.21 micromol L(-1) lower lipoprotein(a) levels than nonusers (P < 0.001 and P=0.04, respectively); these differences were attenuated after accounting for genetic effects in monozygotic twins. Although physically active subjects had higher levels of HDL cholesterol than nonactive subjects, this was nonsignificant after adjusting for genetic factors. CONCLUSIONS Smoking-induced aberrations in HDL cholesterol and triglycerides and alcohol-related differences in LDL cholesterol were independent of genetic influences. The association between smoking and hypertriglyceridaemia was accentuated in high genetic risk individuals.
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Wassell RW, Adams N, Kelly PJ. Treatment of temporomandibular disorders by stabilising splints in general dental practice: results after initial treatment. Br Dent J 2004; 197:35-41; discussion 31; quiz 50-1. [PMID: 15243608 DOI: 10.1038/sj.bdj.4811420] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2003] [Accepted: 08/06/2003] [Indexed: 11/09/2022]
Abstract
INTRODUCTION Little is known about how effective general dental practitioners (GDPs) are in treating temporomandibular disorders (TMD). The overall aim of this study was to compare the lower stabilising splint (SS) with a non-occluding control (CS) for the management of TMD in general dental practice. METHOD A total of 93 TMD patients attending 11 GDPs were randomly allocated to SS or CS. Diagnosis was according to International Headache Society Criteria. Outcome criteria included pain visual analogue scale (VAS), number of tender muscles, aggregate joint tenderness, inter-incisal opening, TMJ clicks and headaches. Splints were fitted one week after baseline and patients were followed-up every three weeks to three months; those not responding to CS after six weeks (< 50% VAS reduction) were crossed over to SS for a further three months. RESULTS Documentation was returned from nine GDPs for 72 patients (38 for SS, 34 for CS). At six weeks, mean improvements were noted for all outcome criteria, but less so for clicking. There were no significant differences between splints [chi(2)]. Seventeen CS patients had < 50% VAS reduction and were provided with SS in the cross-over group. CS patients with >50% VAS reduction were significantly younger than CS patients who crossed-over (ANOVA, p=0.009) and had significantly less diagnoses of TMJ clicking (chi(2), p<0.05). At the conclusion of the trial 16 patients were referred for specialist management: 11 non-responders (< 50% VAS reduction), one of whom needed occlusal adjustment and five responders also needing occlusal adjustment. CONCLUSIONS At six weeks SS gave similar relief to CS for all outcome criteria. Patients who crossed-over from CS to SS were more likely to be older and have clicking TMJs. At the end of treatment nine of 11 non-responders to SS had a diagnosis of disc displacement with reduction. However, 80% TMD patients were managed effectively by GDPs using splints for periods of up to five months.
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Abstract
BACKGROUND Atrial fibrillation (AF), an important and treatable cause of ischaemic stroke, can occur as a sustained or a paroxysmal arrhythmia. Continuous cardiac rhythm monitoring (Holter monitoring) is often performed in stroke patients to identify paroxysmal AF, which is an indication for warfarin anti-coagulation in this patient population. AIM The aim of this study was to assess the clinical utility of Holter monitoring in detecting occult AF in patients with possible cardioembolic stroke. METHODS The medical records of ischaemic stroke patients consecutively hospitalized at a single academic centre during a one-year period were reviewed. Data regarding patient demographics, stroke characteristics, electrocardiography and echocardiography results and duration and findings of Holter monitoring were abstracted. The primary outcome was yield of newly diagnosed AF on Holter monitoring. RESULTS Of 465 consecutive patients admitted with a diagnosis of new ischaemic stroke, 210 underwent Holter monitoring. The mean duration of monitoring was 22.8 +/- 4.0 h. Previously undiscovered AF was -identified in five cases (2.4%), all of which represented non-rheumatic AF. In three cases, the Holter test was negative despite AF documented on an admission electro-cardiogram. CONCLUSIONS Holter monitoring can identify occult paroxysmal AF, assisting targeted secondary prevention in patients with new ischaemic stroke. However, the standard 24-h duration of monitoring probably under-estimates the prevalence of paroxysmal AF in this population. Prospective studies are indicated to evaluate the value of longer monitoring periods in stroke populations.
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Greenfield JR, Samaras K, Jenkins AB, Kelly PJ, Spector TD, Gallimore JR, Pepys MB, Campbell LV. Obesity is an important determinant of baseline serum C-reactive protein concentration in monozygotic twins, independent of genetic influences. Circulation 2004; 109:3022-8. [PMID: 15184288 DOI: 10.1161/01.cir.0000130640.77501.79] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
BACKGROUND C-reactive protein (CRP) values predict atherothrombotic cardiovascular disease and type 2 diabetes mellitus. Associations between CRP and obesity, predominantly assessed anthropometrically, may partly explain these observations. Previous studies have been unable to control for genetic influences on CRP and obesity. The aim of this study was to examine the relationship between CRP and accurately measured body fat, lipids, apolipoproteins, blood pressure, and environmental and behavioral factors, independent of genetic influences. METHODS AND RESULTS One hundred ninety-four healthy female twins (age 57.2+/-7 years) were studied after excluding pairs with CRP values >10 mg/L. Total body fat and central abdominal fat (CAF) were measured by dual-energy x-ray absorptiometry. CRP concentration was strongly related to surrogate and direct measures of body fat (r=0.31 to 0.54, P<0.001), diastolic blood pressure (r=0.20, P=0.003), and lipid and apolipoprotein levels (r=0.21 to 0.51, P<0.008). Light-to-moderate alcohol consumers and nonusers of hormone replacement therapy (HRT) had lower CRP levels than abstainers and HRT users, respectively. In stepwise multiple regression analysis, CAF, triglycerides, apolipoprotein B, and HRT use explained 46% of the variance in circulating CRP. In analyses controlling for genetic influences in monozygotic twins, within-pair differences in CRP were associated with within-pair differences in total body fat (r=0.39, P<0.001), CAF (r=0.34, P=0.002), diastolic blood pressure (r=0.24, P=0.03), apolipoprotein AI (r=-0.33, P=0.01), HDL cholesterol (r=-0.42, P=0.001), and triglycerides (r=0.35, P=0.007). CONCLUSIONS CRP was strongly related to total and central abdominal obesity, blood pressure, and lipid levels, independent of genetic influences. These relationships are likely to contribute significantly to prospective associations between CRP and type 2 diabetes and coronary events.
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Kim R, Alterman R, Kelly PJ, Fazzini E, Eidelberg D, Beric A, Sterio D. Efficacy of bilateral pallidotomy. Neurosurg Focus 2004; 2:e8. [PMID: 15096015 DOI: 10.3171/foc.1997.2.6.9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Unilateral pallidotomy is a safe and effective treatment for medically refractory bradykinetic Parkinson's disease, especially in those patients with levodopa-induced dyskinesia and severe on-off fluctuations. The efficacy of bilateral pallidotomy is less certain. The authors completed 11 of 12 attempted bilateral pallidotomies among 150 patients undergoing pallidotomy at New York University. In all but one patient, the pallidotomies were separated by at least 9 months. Patients were selected for bilateral pallidotomy if they exhibited bilateral rigidity, bradykinesia, or levodopa-induced dyskinesia prior to treatment or if they exhibited disease progression contralateral to their previously treated side. The Unified Parkinson's Disease Rating Scale (UPDRS) and timed upper-extremity tasks of the Core Assessment Protocol for Intracerebral Transplantation (CAPIT) were administered to all 12 patients in the "off" state (12 hours without receiving medications) preoperatively and again at 6 and 12 months after each procedure. The median UPDRS and contralateral CAPIT scores improved 60% following the initial procedure (p = 0.008, Wilcoxon rank sums test). The second pallidotomy generated only an additional 10% improvement in the UPDRS and CAPIT scores ipsilateral to the original procedure (p = 0.05). Worsened speech was observed in two cases. In the 12th case, total speech arrest was noted during test stimulation. Speech returned within minutes after stimulation was halted. Lesioning was not performed. These results indicate that bilateral pallidotomy has a narrow therapeutic window. Motor improvement ipsilateral to the first lesion leaves little room for further improvement from the second lesion and the risk of speech deficit is greatly enhanced. Chronic pallidal stimulation contralateral to a previously successful pallidotomy may prove to be a safer alternative for the subset of patients who require bilateral procedures.
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Kawaguchi M, Drummond JC, Cole DJ, Kelly PJ, Spurlock MP, Patel PM. Effect of isoflurane on neuronal apoptosis in rats subjected to focal cerebral ischemia. Anesth Analg 2004; 98:798-805, table of contents. [PMID: 14980940 DOI: 10.1213/01.ane.0000105872.76747.f6] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
UNLABELLED Although isoflurane can reduce ischemic neuronal injury after short postischemic recovery intervals, this neuroprotective efficacy is not sustained. Neuronal apoptosis can contribute to the gradual increase in infarct size after ischemia. This suggests that isoflurane, although capable of reducing early neuronal death, may not inhibit ischemia-induced apoptosis. We investigated the effects of isoflurane on markers of apoptosis in rats subjected to focal ischemia. Fasted Wistar-Kyoto rats were anesthetized with isoflurane and randomly allocated to awake (n = 40) or isoflurane (n = 40) groups. Animals in both groups were subjected to focal ischemia by filament occlusion of the middle cerebral artery for 70 min. Pericranial temperature was servo-controlled at 37 degrees C +/- 0.2 degrees C throughout the experiment. In the awake group, isoflurane was discontinued and the animals were allowed to awaken. In the isoflurane group, isoflurane anesthesia was maintained at 1.5 MAC (minimum alveolar anesthetic concentration). Animals were killed 7 h, 1 day, 4 days, or 7 days after reperfusion (n = 10/group/time point). The area of cerebral infarction was measured by image analysis in a hematoxylin and eosin stained section. In three adjacent sections, apoptotic neurons were identified by TUNEL staining and immunostaining for active caspase-9 and caspase-3. Infarct size was smaller in the isoflurane group than the awake group 7 h, 1 day, and 4 days after reperfusion (P < 0.05). However, this difference was absent 7 days after reperfusion. The number of apoptotic (TUNEL, caspase-3, and caspase-9 positive) cells 1 day after ischemia was significantly more in the awake versus isoflurane group. After a recovery period of 4 or 7 days, the number of apoptotic cells in the isoflurane group was more than in the awake group. After 7 days, the number of caspase-3 and -9 positive neurons was more in the isoflurane group (P < 0.05). The data indicate that isoflurane delays but does not prevent the development of cerebral infarction caused by ischemia. Isoflurane reduced the development of apoptosis early after ischemia but did not prevent it at later stages of postischemic recovery. IMPLICATIONS The effect of isoflurane on neuronal apoptosis was investigated in rats subjected to focal cerebral ischemia. In isoflurane-anesthetized animals, ischemia-induced apoptosis occurred during the later stages of postischemic recovery. Isoflurane did not inhibit postischemic neuronal apoptosis.
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Bauer GEW, Brataas A, Tserkovnyak Y, Halperin BI, Zwierzycki M, Kelly PJ. Dynamic ferromagnetic proximity effect in photoexcited semiconductors. PHYSICAL REVIEW LETTERS 2004; 92:126601. [PMID: 15089693 DOI: 10.1103/physrevlett.92.126601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2003] [Indexed: 05/24/2023]
Abstract
The spin dynamics of photoexcited carriers in semiconductors in contact with a ferromagnet is treated theoretically and compared with time-dependent Faraday rotation experiments. The long-time response of the system is found to be governed by the first tens of picoseconds in which the excited plasma interacts strongly with the intrinsic interface between the semiconductor and the ferromagnet in spite of the existence of a Schottky barrier in equilibrium.
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Kelly PJ, Kistler JP, Shih VE, Mandell R, Atassi N, Barron M, Lee H, Silveira S, Furie KL. Inflammation, Homocysteine, and Vitamin B6 Status After Ischemic Stroke. Stroke 2004; 35:12-5. [PMID: 14657454 DOI: 10.1161/01.str.0000106481.59944.2f] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Epidemiological studies have described an association between low vitamin B6 (measured as pyridoxal 5'-phosphate [PLP]) and ischemic stroke, independent of homocysteine (tHcy). We investigated B6 status, tHcy, and inflammation (measured by C-reactive protein [CRP]) in patients with stroke and controls. METHODS Consecutive cases with new ischemic stroke were compared with matched controls. Fasting tHcy, PLP, and CRP were measured. RESULTS The adjusted odds ratio of low PLP in the highest compared with the lowest CRP quartile was 16.6 (2, 139.9, P=0.01). Age, CRP, supplemental vitamin use, and albumin were independent predictors of PLP (P<0.05 for all). No relationship was observed between CRP and tHcy. CONCLUSIONS The relationship between inflammation and low B6 status may partially explain the findings of previous epidemiological studies.
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100
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Greenfield JR, Samaras K, Jenkins AB, Kelly PJ, Spector TD, Campbell LV. Moderate alcohol consumption, dietary fat composition, and abdominal obesity in women: evidence for gene-environment interaction. J Clin Endocrinol Metab 2003; 88:5381-6. [PMID: 14602777 DOI: 10.1210/jc.2003-030851] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
We examined relationships among alcohol intake, dietary fat composition, and total body fat (TBF) and central abdominal fat (CAF), independent of genetic confounders, and evaluated the modulating effect of genetic susceptibility. We studied 334 female twins (57.7 +/- 6.7 yr) after excluding dietary underreporters. Diet was assessed by Food-Frequency Questionnaire and body fat by dual-energy x-ray absorptiometry. Moderate alcohol consumers (12-17.9 g/d) had less TBF (20.6 +/- 5.6 vs. 24.8 +/- 8.4 kg, P = 0.03) and CAF (1.2 +/- 0.6 vs. 1.6 +/- 0.7 kg, P = 0.03) than abstainers. In multiple regression, alcohol consumption remained independently associated with body fat distribution. In cotwin case-control (monozygotic twin) analysis, moderate alcohol consumption accounted for 300 g less CAF, independent of genetic and other environmental factors. Gene-environment interaction analysis indicated that this association was limited to subjects at high genetic risk of abdominal obesity. There was no relationship between dietary fat composition and adiposity. However, in women at low genetic risk of abdominal obesity, subjects with polyunsaturated fat intakes in the highest tertile had about 50% less CAF than subjects with intakes in the lowest tertile (0.9 +/- 0.4 vs. 1.6 +/- 0.4 kg, P = 0.0007), an association absent in subjects with high genetic risk. In conclusion, genetic risk modulates relationships between dietary factors and adiposity. Lower abdominal fat may mediate associations between dietary intake and type 2 diabetes risk.
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