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1031 citation(s) found for "Xu, Clark".

Memory, executive, and multidomain subtle cognitive impairment
Toledo, Jon B. , Bjerke, Maria , Rozycki, Martin, Jack, Clifford R. , Weiner, Michael W. , Arnold, Steven E. , Reiman, Eric M. , Davatzikos, Christos , Shaw, Leslie M. , Trojanowski, John Q. , Initiative, For the Alzheimer's Disease Neuroimaging, Weiner, Michael, Aisen, Paul , Weiner, Michael, Petersen, Ronald, Jagust, William, Trojanowki, John Q., Green, Robert C., Saykin, Andrew J., Liu, Enchi , Green, Robert C., Montine, Tom, Petersen, Ronald, Gamst, Anthony, Thomas, Ronald G. , Walter, Sarah , Gessert, Devon, Sather, Tamie, Kornak, John , Felmlee, Joel P. , Schuff, Norbert, Alexander, Gene E. , DeCarli, Charles, Jagust, William, Bandy, Dan, Foster, Norm, Reiman, Eric M., Mathis, Chet, Cairns, Nigel J. , Taylor‐Reinwald, Lisa, Shaw, Les, Korecka, Magdalena , Crawford, Karen , Neu, Scott, Potkin, Steven, Kachaturian, Zaven, Frank, Richard , Molchan, Susan, Quinn, Joseph, Lind, Betty, Dolen, Sara, Schneider, Lon S. , Pawluczyk, Sonia, Spann, Bryan M., Brewer, James, Vanderswag, Helen, Heidebrink, Judith L. , Petersen, Ronald, Johnson, Kris , Doody, Rachelle S., Chowdhury, Munir , Bell, Karen L. , Leon, Sue, Schneider, Stacy, Marson, Daniel , Griffith, Randall, Clark, David, Grossman, Hillel, Mitsis, Effie, Romirowsky, Aliza, deToledo‐Morrell, Leyla, Duara, Ranjan , Varon, Daniel, Roberts, Peggy, Albert, Marilyn, Onyike, Chiadi, Kielb, Stephanie , Glodzik, Lidia , Santi, Susan De , Doraiswamy, P. Murali , Petrella, Jeffrey R. , Coleman, R. Edward, Arnold, Steven E., Karlawish, Jason , Smith, Charles D., Jicha, Gregory A. , Hardy, Peter , Oakley, MaryAnn, Simpson, Donna M., Goldstein, Bonnie S., Martin, Kim, Makino, Kelly M., Ismail, M. Saleem , Brand, Connie, Mulnard, Ruth A., Thai, Gaby , Mc-Adams-Ortiz, Catherine, Mathews, Dana, Quiceno, Mary , King, Richard, Weiner, Myron, Martin-Cook, Kristen, Devous, Michael D. , Cellar, Janet S., Anderson, Heather S., Swerdlow, Russell H. , Apostolova, Liana , Lu, Po H. , Bartzokis, George, Graff‐Radford, Neill R. , Parfitt, Francine, Farlow, Martin R. , Hake, Ann Marie , Matthews, Brandy R., Herring, Scott, Dyck, Christopher H. van , Carson, Richard E. , MacAvoy, Martha G., Chertkow, Howard, Bergman, Howard , Hosein, Chris, Caldwell, Curtis, Hsiung, Ging‐Yuek Robin , Mudge, Benita, Assaly, Michele, Kertesz, Andrew, Rogers, John, Trost, Dick, Bernick, Charles , Munic, Donna, Mesulam, Marek-Marsel, Lipowski, Kristina, Wu, Chuang‐Kuo, Johnson, Nancy , Sadowsky, Carl, Villena, Teresa, Johnson, Kathleen, Reynolds, Brigid, Johnson, Keith A. , Marshall, Gad A. , Frey, Meghan , Yesavage, Jerome A. , Taylor, Joy L. , Lane, Barton , Rosen, Allyson , Tinklenberg, Jared, Sabbagh, Marwan N. , Belden, Christine M. , Jacobson, Sandra A. , Kowall, Neil W. , Budson, Andrew E. , Johnson, Patricia Lynn, Wolday, Saba, Bwayo, Salome K., Lerner, Alan J. , Hudson, Leon, Ogrocki, Paula, Fletcher, Evan, Olichney, John , Kittur, Smita, Borrie, Michael, Lee, T‐Y, Bartha, Dr Rob, Asthana, Sanjay , Carlsson, Cynthia M., Preda, Adrian , Tariot, Pierre N. , Fleisher, Adam , Reeder, Stephanie, Bates, Vernice, Capote, Horacio, Rainka, Michelle, Kataki, Maria , Zimmerman, Earl A. , Celmins, Dzintra, Brown, Alice D., Blank, Karen, Anderson, Karen, Saykin, Andrew J., Santulli, Robert B. , Schwartz, Eben S., Williamson, Jeff D. , Garg, Pradeep , Watkins, Franklin, Ott, Brian R. , Querfurth, Henry, Tremont, Geoffrey , Salloway, Stephen , Malloy, Paul, Correia, Stephen , Rosen, Howard J. , Mintzer, Jacobo , Longmire, Crystal Flynn, Spicer, Kenneth, Rachinsky, Irina, Rogers, John, Kertesz, Andrew, Drost, Dick, Hernando, Raymundo, Sarrael, Antero, Schultz, Susan K. , Ponto, Laura L. Boles , Shim, Hyungsub , Smith, Karen E. , Relkin, Norman , Chaing, Gloria, Raudin, Lisa, Smith, Amanda , Fargher, Kristin, Raj, Balebail Ashok, Chen, Kewei , Initiative, For the Alzheimer's Disease Neuroimaging, Weiner, Michael, Weiner, Michael, Petersen, Ronald, Jagust, William, Toga, Arthur W. , Beckett, Laurel , Green, Robert C., Saykin, Andrew J., Morris, John C. , Green, Robert C., Petersen, Ronald, Donohue, Michael , Harvey, Danielle , Dale, Anders M. , Bernstein, Matt A. , Fox, Nick C. , Thompson, Paul M. , Jagust, William, Koeppe, Robert A. , Foster, Norm, Reiman, Eric M., Mathis, Chet, Lee, Virginia M.‐Y. , Saykin, Andrew J. , Foroud, Tatiana , Shen, Li , Snyder, Peter J. , Kaye, Jeffrey , Lord, Joanne L. , Petersen, Ronald, Villanueva-Meyer, Javier E. , Stern, Yaakov , Honig, Lawrence S. , Ances, Beau M. , Shah, Raj C. , Duara, Ranjan , Varón, Daniel , Rusinek, Henry , Leon, Mony J. de , Arnold, Steven E., Wolk, David A. , López, Oscar L. , Porsteinsson, Anton P. , Womack, Kyle , Diaz‐Arrastia, Ramon , Levey, Allan I. , Lah, James J. , Burns, Jeffrey M. , Silverman, Daniel H.S. , Johnson, Heather K. , Black, Sandra E. , Stefanovic, Bojana , Feldman, Howard , Kertesz, Andrew, Rogers, John, Kerwin, Diana , Martínez, Walter Fabián , Turner, Raymond Scott , Sperling, Reisa Anne , Killiany, Ronald , Norbash, Alexander , Obisesan, Thomas O. , Carmichael, Owen , Johnson, Sterling C. , Carlsson, Cynthia M. , Potkin, Steven G. , Nguyen, Dana R. , Reeder, Stephanie, Scharre, Douglas W. , Pearlson, Godfrey D. , Saykin, Andrew J., Sink, Kaycee M. , Miller, Bruce L. , Finger, Elizabeth C. , Rogers, John, Kertesz, Andrew, Jack, Clifford R , Preda, Adrian , Hsiung, Gink-Yuek , Jicha, Gregory A

Neurology | June 18, 2015 | Volume: 85 | Issue: 2 | Pages: 144-153

10.1212/wnl.0000000000001738 | PMID 26085606 Get It

Cancer Caregiver: Perceived Benefits of Technology
Atherton, Pamela J., Clark, Matthew M. , Kung, Simon , Sloan, Jeff A. , Rummans, Teresa A. , Lapid, Maria I. , Atherton, Pamela J.

Telemedicine and e-Health | June 15, 2015 | Volume: 21 | Issue: 11 | Pages: 893-902

10.1089/tmj.2014.0117 | PMID 26075800 Get It

Background: The burden associated with caregiving has been well documented. Caregivers have multiple responsibilities, and technology may be accessible as a potential burden-alleviating resource. Materials and Methods: We surveyed cancer caregivers regarding current technology use and willingness to use technology for easing burden or distress. Because age has been associated with technology use, responses were compared between geriatric (≥65 years old) and nongeriatric (18–64 years old) caregivers. Results: We had 112 respondents. Based on nonmissing responses, 66% ( n =71) were women, 95% ( n =106) were white, and 84% ( n =91) had post–high school education. Almost all caregivers reported having Internet (105 [94%]) and e-mail (102 [91%]) access. Nongeriatric caregivers indicated more willingness to access Internet-based tools that help caregivers (54 [93%] versus 41 [76%]; p =0.04) and were more frequent users of social media (37 [64%] versus 16 [30%]; p =0.01), smartphones (33 [57%] versus 16 [30%]; p =0.01), and other mobile wireless devices (42 [72%] versus 19 [35%]; p <0.001) than geriatric caregivers. They also more frequently expected technologies to improve their own quality of life ( p =0.009), increase their feelings of being effective as a caregiver ( p =0.02), and save time ( p =0.003). Regardless of age, a majority of caregivers (67 [62%]) endorsed the potential benefit of caregiving technologies in preventing burnout. Conclusions: Most caregivers have high access to and use of technology. Geriatric and nongeriatric caregivers were receptive to technology-based tools to help with their caregiving roles. Although nongeriatric caregivers expected to derive more benefit from such tools, both groups believed that caregiving technologies could reduce burden.
Pancreatic oncogenic signaling cascades converge at Protein Kinase D1
Leitges, Michael , Störz, Peter , Liou, Geou‐Yarh , Leitges, Michael

Cell Cycle | May 21, 2015 | Volume: 14 | Issue: 10 | Pages: 1489-1490

10.1080/15384101.2015.1032646 | PMID 25928263 Get It

Spiritual Well-Being and Spiritual Practices in Elderly Depressed Psychiatric Inpatients
Piderman, Katherine M. , Stevens, Susanna R., Somers, Kristin J., Kronberg, Matthew T., Clark, Matthew M. , Rummans, Teresa A. , Lapid, Maria I. , Ryan, Susan

Journal of Pastoral Care & Counseling: Advancing theory and professional practice through scholarly and reflective publicati | May 18, 2015 | Volume: 65 | Issue: 1 | Pages: 1-11

10.1177/154230501106500103 | PMID 22452149 Get It

This study's aims were to describe the spirituality of depressed elderly psychiatric inpatients and to examine associations among spirituality, depression, and quality of life (QOL). Forty-five persons participated. Most reported frequent, stable spiritual practices and experiencing spiritual comfort and guidance. Some reported spiritual distress and changes in spirituality. During hospitalization, participants demonstrated increased spiritual well-being (SWB) and peacefulness, and reduced hopelessness, worthlessness, and guilt. Positive associations were found between SWB and QOL and negative associations between SWB and depression.
Effects of Age, Sex, and Body Position on Orofacial Muscle Tone in Healthy Adults
Dietsch, Angela M. , Steiner, Jessica N., Solomon, Nancy Pearl , Clark, Heather M. , Solomon, Nancy Pearl

Journal of Speech, Language, and Hearing Research | May 7, 2015 | Volume: 58 | Issue: 4 | Pages: 1145-1150

10.1044/2015_jslhr-s-14-0325 | PMID 25951413 Get It

PurposeQuantification of tissue stiffness may facilitate identification of abnormalities in orofacial muscle tone and thus contribute to differential diagnosis of dysarthria. Tissue stiffness is affected by muscle tone as well as age-related changes in muscle and connective tissue.MethodThe Myoton-3 measured tissue stiffness in 40 healthy adults, including equal numbers of men and women in each of two age groups: 18–40 years and 60+ years. Data were collected from relaxed muscles at the masseter, cheek, and lateral tongue surfaces in two positions: reclined on the side and seated with head tilted.ResultsTissue stiffness differed across age, sex, and measurement site with multiple interaction effects. Overall, older subjects exhibited higher stiffness coefficients and oscillation frequency measures than younger subjects whereas sex differences varied by tissue site. Effects of body position were inconsistent across tissue site and measurement.ConclusionsAlthough older subjects were expected to have lower muscle tone, age-related nonmuscular tissue changes may have contributed to yield a net effect of higher stiffness. These data raise several considerations for the development of accurate normative data and for future diagnostic applications of tissue stiffness assessment.
Abstract 2737: Modulation of mitotic DNA damage as a paradigm for glioblastoma therapy
Shen, Ying , Nitta, Masayuki, Futalan, Diahnn, Taich, Zack, Treiber, Jeffrey M. , Stevens, Deanna M., Chen, Hongzhuan , Wakosky, Jill, Chen, Clark C. , Li, Jie , Steed, Tyler , Taich, Zack, Schroeder, Mark A. , Sarkaria, Jann N. , Jiang, Tao , Carter, Bob S. , Esashi, Fumiko , Furnari, Frank B. , Cavenee, Webster K. , Desai, Arshad

Cancer Research | May 4, 2015 | Volume: 74 | Issue: 19_Supplement | Pages: 2737-2737

10.1158/1538-7445.am2014-2737 Get It

Abstract The clinical efficacies of molecularly targeted glioblastomas therapies have been vastly disappointing. The multitudes of resistance mechanisms suggest that glioblastomas possess highly dynamic molecular circuits grounded in functional redundancy. Emerging data suggests that the expression of functionally redundant oncogenes induced similar forms of cellular stress, requiring hyper-activation of common compensatory pathways to ensure cell viability. Targeting these pathways, therefore, afford potential opportunities for tumor ablation while by-passing the redundancy of oncogenic circuitry. To explore this paradigm, we carried out a siRNA screen to identify synthetic lethal partners of the oncogenic Epidermal Growth Factor Receptor variant III (EGFRvIII) in glioblastoma cells and identified Polo-Like Kinase 1 (PLK1). Treatment using a PLK1 inhibitor, BI2536, or siRNAs induced preferential toxicity to the EGFRvIII expressing glioblastoma cells in multiple in vitro (serum and neurosphere lines) and in vivo models (heterotopic and orthotopic xenograft models). Consistent with the heightened PLK1 requirement, EGFRvIII expressing glioblastomas harbored increased levels of the p-Thr210 PLK1 (an activated form of PLK1). Inhibition of PLK1 by BI2536 treatment induced an increase in the proportion of cells that co-stained for p-Histone H3 and γH2AX foci, suggesting accumulation of mitotic DNA damage. This effect was exacerbated by EGFRvIII expression, implicating induction of mitotic DNA damage as a major contributor to the observed synthetic lethality. Consistent with this observation, EGFRvIII expression induced the formation of aberrant mitosis as well as prolonged mitotic progression. Further supporting an essential role for PLK1 in suppressing DNA damage accumulation, BI2536 treatment significantly enhanced the tumoricidal effect of the DNA damaging chemotherapy, temozolomide. Mechanistically, inhibition of PLK1 suppressed the expression of Rad51, the accumulation of pS14 Rad51 (an active form of Rad51), as well as overall homologous recombination efficiency in vitro. We validated the clinical pertinence of these results using three clinically annotated glioblastoma databases (TCGA, REMEBMRANDT, CGGA). In all three datasets, increased expression of a PLK1 signature consistently associated with increased expression of HR genes and lowered gene expression signature associated with DNA damage accumulation. Supporting our proposed paradigm, the tumoricidal effect of BI2536 was universally observed in a panel of eight murine ink4a/arf (-/-) EGFRvIII expressing glioblastoma clones that developed resistance to EGFR inhibitors by distinct and independent mechanisms. In aggregate, our results support the essential role of PLK1 in suppressing mitotic DNA damage and provide a novel framework for glioblastoma therapy. Citation Format: Ying Shen, Masayuki Nitta, Jie Li, Diahnn Futalan, Tyler Steed, Zack Taich, Jeffrey M. Treiber, Deanna Stevens, Mark A. Schroeder, Jann N. Sarkaria, Hong-Zhuan Chen, Tao Jiang, Bob S. Carter, Fumiko Esashi, Jill Wakosky, Frank Furnari, Webster K. Cavenee, Arshad Desai, Clark C. Chen. Modulation of mitotic DNA damage as a paradigm for glioblastoma therapy. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2737. doi:10.1158/1538-7445.AM2014-2737
An international randomised trial of celecoxib versus celecoxib plus difluoromethylornithine in patients with familial adenomatous polyposis
Lynch, Patrick M, Burke, Carol A. , Phillips, Robin, Morris, Jeffrey S. , Slack, Rebecca, Wang, Xuemei , Liu, Jun , Patterson, Sherri, Rodrı́guez-Bigas, Miguel A. , Half, Elizabeth , Bülow, Steffen, Latchford, Andrew , Clark, Sue, Ross, William A., Malone, Bonnie, Hasson, Hennie, Hawk, Ernest T. , Lynch, Patrick M, Sinicrope, Frank A. , Richmond, Ellen S. , Burke, Carol A

Gut | March 20, 2015 | Volume: 65 | Issue: 2 | Pages: 286-295

10.1136/gutjnl-2014-307235 | PMID 25792707 Get It

Background and aim Although Non-steroidal anti-inflammatory drugs reduce colorectal adenoma burden in familial adenomatous polyposis (FAP), the utility of combining chemopreventive agents in FAP is not known. We conducted a randomised trial of celecoxib (CXB) versus CXB+diflouromethylornithine (DFMO) to determine the synergistic effect, if any. Methods The primary endpoint was % change in adenoma count in a defined field. Secondary endpoints were adenoma burden (weighted by adenoma diameter) and video review of entire colon/rectal segments. Adverse event (AEs) were monitored by National Cancer Institution toxicity criteria. Results 112 subjects were randomised: 60 men and 52 women at a mean age of 38 years. For the 89 patients who had landmark-matched polyp counts available at baseline and 6 months, the mean % change in adenoma count over the 6 months of trial was −13.0% for CXB+DFMO and −1.0% for CXB (p=0.69). Mean % change in adenoma burden was −40% (CXB+DFMO) vs −27% (CXB) (p=0.13). Video-based global polyp change was −0.80 for CXB+DFMO vs −0.33 for CXB (p=0.03). Fatigue was the only significant AE, worse on the CXB arm (p=0.02). Conclusions CXB combined with DFMO yielded moderate synergy according to a video-based global assessment. No significant difference in adenoma count, the primary endpoint, was seen between the two study arms. No evidence of DFMO-related ototoxicity was seen. There were no adverse cardiovascular outcomes in either trial arm and no significant increase in AEs in the CXB+DFMO arm of the trial. Differences in outcomes between primary and secondary endpoints may relate to sensitivity of the endpoint measures themselves. Trial registration number ClinicalTrials.gov number N01-CN95040.
Increased incidence of malignant melanoma and other rare cutaneous cancers in the setting of chronic lymphocytic leukemia
Brewer, Jerry D., Call, Timothy G. , Roenigk, Randall K., Weaver, Amy L. , Otley, Clark C. , Shanafelt, Tait D. , Cerhan, James R.

International Journal of Dermatology | March 14, 2015 | Volume: 54 | Issue: 8 | Pages: No page available

10.1111/ijd.12564 | PMID 25772131 Get It

AbstractBackgroundPatients with chronic lymphocytic leukemia (CLL), small lymphocytic lymphoma (SLL), or non‐Hodgkin lymphoma (NHL) are at increased risk for the development of skin malignancies.ObjectivesThis study was conducted to estimate the incidences of rare skin malignancies in patients with CLL/SLL or NHL.MethodsPatients with a diagnosis of CLL/SLL or NHL recorded in the Surveillance, Epidemiology and End Results (SEER) database during 1992–2007 were identified. Diagnoses of specific skin malignancies were identified from SEER files.ResultsDuring 1992–2007, a total of 128,674 patients with first diagnoses of CLL/SLL or NHL were recorded in SEER; 4743 were excluded because follow‐up data were unavailable. Among the remaining 123,931 patients, 28,964 had CLL/SLL and 94,967 had NHL. Standardized incidence ratios (SIRs) for invasive malignant melanoma, Merkel cell carcinoma, malignant fibrous histiocytoma, dermatofibrosarcoma protuberans, Kaposi's sarcoma, and sebaceous carcinoma were 2.3, 8.2, 3.6, 2.5, 2.9, and 1.4, respectively, in CLL/SLL patients and 1.6, 3.2, 1.5, 1.3, 17.6, and 0.8, respectively, in NHL patients. When invasive melanoma was stratified by patient age and sex, the highest SIR (17.8) was found in men aged 0–49 years with CLL (P < 0.001).ConclusionsPatients with CLL/SLL or NHL have a higher risk for the subsequent development of rare skin cancers. Given the more aggressive nature of these malignancies in this setting, regular monitoring for the development and prompt treatment of cutaneous malignancy is prudent in patients with NHL and particularly in patients with CLL. Regular use of sun protection may decrease the morbidity associated with skin cancer in this immunosuppressed population.
Off-Label Use of Inhaled Nitric Oxide After Release of NIH Consensus Statement
Ellsworth, Marc A., Harris, Malinda N. , Carey, William A., Spitzer, Alan R., Clark, Reese H.

Pediatrics | March 10, 2015 | Volume: 135 | Issue: 4 | Pages: 643-648

10.1542/peds.2014-3290 | PMID 25755237 Get It

BACKGROUND:Inhaled nitric oxide (iNO) therapy is an off-label medication in infants &lt;34 weeks’ gestational age. In 2011, the National Institutes of Health released a statement discouraging routine iNO use in premature infants. The objective of this study was to describe utilization patterns of iNO in American NICUs in the years surrounding the release of the National Institutes of Health statement. We hypothesized that iNO prescription rates in premature infants have remained unchanged since 2011.METHODS:The Pediatrix Medical Group Clinical Data Warehouse was queried for the years 2009–2013 to describe first exposure iNO use among all admitted neonates stratified by gestational age.RESULTS:Between 2009 and 2013, the rate of iNO utilization in 23- to 29-week neonates increased from 5.03% to 6.19%, a relative increase of 23% (confidence interval: 8%–40%; P = .003). Of all neonates who received iNO therapy in 2013, nearly half were &lt;34 weeks’ gestation, with these infants accounting for more than half of all first exposure iNO days each year of the study period.CONCLUSIONS:The rates of off-label iNO use in preterm infants continue to rise despite evidence revealing no clear benefit in this population. This pattern of iNO prescription is not benign and comes with economic consequences.
Effects of chronic sympathectomy on vascular function in the human forearm
Eisenach, John H., Clark, Erin S., Charkoudian, Nisha , Atkinson, John L. D., Fealey, Robert D., Dietz, Niki M., Joyner, Michael J. , Dinenno, Frank A. , Joyner, Michael J

Journal of Applied Physiology | March 3, 2015 | Volume: 92 | Issue: 5 | Pages: 2019-2025

10.1152/japplphysiol.01025.2001 | PMID 11960953 Get It

To determine whether endothelial function is altered by chronic surgical sympathectomy, we infused ACh, isoproterenol, nitroprusside (NTP), and the nitric oxide synthase inhibitor N G-mono-methyl-l-arginine (l-NMMA) into the brachial arteries of nine patients 5–64 mo after thoracic sympathectomy for hyperhidrosis. Age- and gender-matched controls were also studied. Forearm blood flow (FBF) was measured by venous occlusion plethysmography. Lower body negative pressure was used to assess reflex vasoconstrictor responses. Tyramine, which acts locally and causes norepinephrine release from sympathetic nerves, was also administered via the brachial artery. FBF at rest was 2.5 ± 0.4 ml · dl−1 · min−1 in the patients and 2.5 ± 0.3 ml · dl−1 · min−1 in the controls ( P = 0.95). The normal vasoconstrictor responses to lower body negative pressure were abolished in the patients. By contrast, tyramine produced dose-dependent vasoconstriction in the patients that was identical to that of controls. The dose-response curves to ACh were similar in patients and controls, with maximum values of 19.3 ± 4.4 vs. 25.5 ± 2.8 ml · dl−1 · min−1, respectively. l-NMMA reduced baseline FBF similarly and reduced the maximal FBF response to ACh in both groups (patients 8.9 ± 3.5 vs. controls 9.7 ± 2.5 ml · dl−1 · min−1). The vasodilation to isoproterenol was similar and blunted to the same extent in both groups by l-NMMA. The responses to NTP in patients and controls were similar and not affected byl-NMMA. We conclude that, in humans, chronic surgical sympathectomy does not cause major disruptions in vascular function in the forearm. The normal vasoconstrictor responses to tyramine indicate that there were viable sympathetic nerves in the forearm that were not engaged by LBNP.