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12579 citation(s) found for "Ma, John".

Arterioventricular Coupling and Ventricular Efficiency After Antihypertensive Therapy
Osranek, Martin, Eisenach, John H., Khandheria, Bijoy K. , Chandrasekaran, Krishnaswamy , Seward, James B., Bëlohlávek, Marek

Hypertension | December 25, 2007 | Volume: 51 | Issue: 2 | Pages: 275-281

10.1161/hypertensionaha.107.097964 | PMID 18158354 Get It

Patients with hypertension exhibit impaired energetic coupling between the ventricle and the arterial system, leading to reduced cardiac mechanic efficiency and exercise capacity. We tested whether blood pressure normalization with current antihypertensive therapy can improve arterioventricular coupling. Eighteen hypertensive patients without other cardiovascular disease were examined before and after antihypertensive therapy. Transthoracic echocardiography was performed. Central aortic pressure waveforms, including end-systolic pressure, were derived from radial artery applanation tonometry. Afterload was increased with isometric handgrip exercise. Central aortic end-systolic pressure and ventricular volumes at rest and handgrip were used to calculate ventricular elastance, effective arterial elastance, arterioventricular coupling (effective arterial elastance/ventricular elastance), and mechanical efficiency. After 142±67 days, systolic blood pressure decreased from 150.9±14.6 to 119.8±9.2 mm Hg ( P <0.00001), diastolic blood pressure from 85.9±14.8 to 68.8±8.4 mm Hg ( P =0.00002), and cardiac output from 5.8±1.7 to 4.9±1.8 L/min ( P =0.03). Resting left ventricular end-systolic volume, ejection fraction, and septal thickness did not change. Ventricular elastance increased from 1.7±1.0 to 3.2±1.4 mm Hg/mL ( P =0.00002), whereas effective arterial elastance decreased from 1.4±0.5 to 1.2±0.4 mm Hg/mL ( P =0.02). Effective arterial elastance/ventricular elastance decreased in all patients, from 1.1±0.8 to 0.4±0.2 ( P =0.0002). Efficiency improved at rest (72.9±5.8% versus 83.5±5.7%; P <0.00001) and during handgrip (63.5±7.8% versus 78.9±7.1%; P <0.00001). In hypertensive patients, optimal brachial and central blood pressure reduction shifts arterioventricular coupling from cardiac output maximization to ventricular mechanical efficiency optimization. This occurs before significant changes in ventricular geometry and may be responsible for early clinical improvements.
A Psychiatric Perspective of Dialysis Discontinuation
Cohen, Lewis M. , Bostwick, John , Mirot, Adam, Garb, Jane, Braden, Gregory L. , Germain, Michael J.

Journal of Palliative Medicine | December 20, 2007 | Volume: 10 | Issue: 6 | Pages: 1262-1265

10.1089/jpm.2007.0054 | PMID 18095804 Get It

In the 1970s, the suicide rate of patients with end-stage renal disease (ESRD) was calculated by conflating deaths from obvious clinical suicide attempts with deaths caused by lethal noncompliance and deaths preceded by dialysis discontinuation. Three decades later, although society's view about cessation of life-support treatment has markedly changed, relatively little is known about the psychiatric aspects of dialysis discontinuation. This paper reviews the literature and suggests a number of findings that warrant further research investigation.
Mineralocorticoid Signaling in Transition to Heart Failure With Normal Ejection Fraction
Shapiro, Brian P. , Owan, Theophilus , Mohammed, Selma F. , Krüger, Martina , Linke, Wolfgang A. , Burnett, John C. , Redfield, Margaret M. , Linke, Wolfgang A

Hypertension | December 18, 2007 | Volume: 51 | Issue: 2 | Pages: 289-295

10.1161/hypertensionaha.107.099010 | PMID 18086943 Get It

Heart failure with normal ejection fraction occurs in elderly patients with hypertensive heart disease. We hypothesized that, in such patients, mineralocorticoid receptor activation accelerates the types of ventricular and vascular remodeling and dysfunction believed important in the transition to heart failure. We tested this hypothesis by administering deoxycorticosterone acetate (DOCA) without salt loading or nephrectomy to elderly dogs with experimental hypertension. Elderly dogs were made hypertensive by renal wrapping. After 5 weeks, dogs were randomly assigned to DOCA (1 mg/kg per day IM; old hypertensive [OH]+DOCA; n=11) or not (OH; n=11) for 3 weeks. At week 8, conscious echocardiography and hemodynamic assessment under anesthesia were performed. DOCA resulted in further increases in conscious blood pressure ( P <0.05) without increases in cardiac output or diastolic volume. In the conscious state, effective arterial elastance ( P <0.05) and systemic vascular resistance ( P =0.06) were increased, and systemic arterial compliance ( P <0.05) was decreased in OH+DOCA animals. After anesthesia, instrumentation, and autonomic blockade, blood pressure was lower, whereas left ventricular (LV) systolic elastance, LV diastolic stiffness, and ex vivo myofiber diastolic stiffness were increased in OH+DOCA animals. LV collagen was increased in OH+DOCA animals ( P <0.05 for all), but LV mass, LV brain natriuretic peptide, and titin isoform profiles were not. Neither aortic stiffness nor aortic structure was altered in OH+DOCA animals. These findings suggest that age and hypertensive heart disease enhance sensitivity to exogenous mineralocorticoid administration and that mineralocorticoid receptor activation could contribute to the transition to heart failure in elderly persons by promoting increases in LV diastolic and systolic stiffness.
Endoscopically assisted decompression of the suprascapular nerve in the supraspinous fossa: a cadaveric feasibility study
Tubbs, R. Shane , Loukas, Marios , Shoja, Mohammadali M. , Spinner, Robert J. , Middlebrooks, Erik H. , Stetler, William R. , Acakpo‐Satchivi, Leslie, Wellons, John C. , Blount, Jeffrey P. , Oakes, W. Jerry, Middlebrooks, Erik H

Journal of Neurosurgery | December 13, 2007 | Volume: 107 | Issue: 6 | Pages: 1164-1167

10.3171/jns-07/12/1164 | PMID 18077954 Get It

Object The suprascapular nerve may become entrapped as it travels deep to the suprascapular ligament, necessitating decompression. The present study was performed to verify the feasibility of a minimally invasive, endoscopically assisted technique for decompressing the suprascapular nerve in the supraspinous fossa. Methods The authors performed dissection and decompression of the suprascapular ligament using an endoscopically assisted technique via a 3-cm skin incision in 10 adult cadavers (20 sides). Measurements were also made of the depth from the skin to the suprascapular ligament. Results A mean depth of 4 cm was necessary to reach the suprascapular ligament from the skin surface. With the authors' approach, no obvious injury occurred to the suprascapular or other vicinal neurovascular structures (such as the spinal accessory nerve and suprascapular vessels). Conclusions The results of this cadaveric study demonstrate that access to the suprascapular nerve can be obtained endoscopically via a small suprascapular incision. This approach obviates a large incision, entry into the glenohumeral joint, and reduces the risk of spinal accessory nerve injury in the posterior cervical triangle, or atrophy of the trapezius or supraspinatus muscles from a standard larger dissection. To the authors' knowledge an endoscopically assisted approach to decompressing the suprascapular nerve as it courses deep to the suprascapular ligament has not been reported previously.
Upcoming Changes for Authors
Noseworthy, John H.

Neurology | December 10, 2007 | Volume: 69 | Issue: 24 | Pages: 2192-2192

10.1212/01.wnl.0000298808.89852.15 Get It

Sublethal Concentrations of Antibiotics, Effects on Bacteria and the Immune System
Atkinson, Barbara, Washington, John A., Amaral, Leonard

CRC Critical Reviews in Microbiology | December 8, 2007 | Volume: 9 | Issue: 2 | Pages: 101-138

10.3109/10408418209104487 | PMID 7042209 Get It

Variants on 9p24 and 8q24 Are Associated with Risk of Colorectal Cancer: Results from the Colon Cancer Family Registry
Poynter, Jenny N. , Figueiredo, Jane C. , Conti, David V. , Kennedy, Kathleen , Gallinger, Steven , Thibodeau, Stephen N. , Jenkins, Mark A. , Byrnes, Graham , Goode, Ellen L. , Tiirikainen, Maarit , Lindor, Noralane M. , Grove, John, Jass, Jeremy R., Young, Joanne , Potter, John D. , Haile, Robert W. , Duggan, David , CFR, for the Colon, Siegmund, Kimberly D. , Casey, Graham , Hopper, John L. , Baron, John A. , Newcomb, Polly A. , Marchand, Loı̈c Le , CFR, for the Colon, Jenkins, Mark A , Haile, Robert W , Potter, John D , Conti, David V

Cancer Research | December 3, 2007 | Volume: 67 | Issue: 23 | Pages: 11128-11132

10.1158/0008-5472.can-07-3239 | PMID 18056436 Get It

Abstract Recent publications have reported that common variants on 8q24 are associated with both prostate and colorectal cancers (CRC). In addition, one of these studies (the ARCTIC study) initially observed an association with a single nucleotide polymorphism (SNP) on 9p24 that was not confirmed in some of their validation data sets. In the research described here, we conducted a case-unaffected sibling analysis using population- and clinic-based discordant sibships (N = 1,567 sibships) from the Colon Cancer Family Registry (Colon CFR) to investigate the associations between common variants at 9p24 and 8q24 and risk of CRC. We also evaluated whether these associations differed by age, family history, and tumor characteristics, including microsatellite instability and tumor site. Associations were estimated using conditional logistic regression, treating sibship as the matching factor. Analyses were adjusted for age and sex, and stratified by ascertainment source (population versus clinic). We observed an association between a SNP on 9p24 (rs719725) and risk of CRC in the population-based series (AA versus CC: odds ratios, 1.46; 95% confidence interval, 1.06–2.02; AC versus CC: odds ratios, 1.50; 95% confidence interval, 1.14–1.98; P = 0.011 on 2 df). In the population-based series, we also detected statistically significant associations between two SNPs on 8q24, rs10505477 and rs6983267, and risk of CRC (P = 0.005 and P = 0.002, respectively). There was no evidence of statistically significant heterogeneity by age at diagnosis, family history of CRC, microsatellite instability, or tumor site at either locus and no evidence of interaction between SNPs on 8q24 and 9p24. These data suggest that common variants may play important roles in the risk of CRC. [Cancer Res 2007;67(23):11128–32]
Listener Agreement for Auditory-Perceptual Ratings of Dysarthria
Bunton, Kate , Kent, Raymond D. , Rosenbek, John C., Kent, Jane F., Duffy, Joseph R.

Journal of Speech, Language, and Hearing Research | November 30, 2007 | Volume: 50 | Issue: 6 | Pages: 1481-1495

10.1044/1092-4388(2007/102) | PMID 18055769 Get It

Purpose Darley, Aronson, and Brown (1969a, 1969b) detailed methods and results of auditory-perceptual assessment for speakers with dysarthrias of varying etiology. They reported adequate listener reliability for use of the rating system as a tool for differential diagnosis, but several more recent studies have raised concerns about listener reliability using this approach. Method In the present study, the authors examined intrarater and interrater agreement for perceptual ratings of 47 speakers with various dysarthria types by 2 listener groups (inexperienced and experienced). The entire set of perceptual features proposed by Darley et al. was rated based on a 40-s conversational speech sample. Results No differences in levels of agreement were found between the listener groups. Agreement was within 1 scale value or better for 67% of the pairwise comparisons. Levels of agreement were lower when the average rating fell in the mid-range of the scale compared with samples that had an average rating near either of the scale endpoints; agreement was above chance level. No significant differences in agreement were found between the perceptual features. Discussion The levels of listener agreement that were found indicate that auditory-perceptual ratings show promise during clinical assessment for identifying salient features of dysarthria for speakers with various etiologies.
Bacterial and Viral Throat Flora
Hable, Kathleen A., Washington, John A., Herrmann, Ernest C.

Clinical Pediatrics | November 26, 2007 | Volume: 10 | Issue: 4 | Pages: 199-203

10.1177/000992287101000405 | PMID 4396432 Get It

Physiologic Mechanisms of Jaundice in the Newborn
Metge, William R., Foulk, William T., Dower, John C.

Clinical Pediatrics | November 26, 2007 | Volume: 1 | Issue: 1 | Pages: 152-156

10.1177/000992286200100130 | PMID 13935182 Get It