Biomedical subjects

W R Wayne Martin

Publications and source records attributed to W R Wayne Martin.

9 recordsLinked to original sources

PubMed2007

Magnetic resonance spectroscopic evidence for presupplementary motor area neuronal dysfunction in Parkinson's disease.

The anterior cingulate (AC) gyrus and the presupplementary motor area (pre-SMA) show pathological changes in Parkinson's disease (PD). We examined if PD patients show magnetic resonance spectroscopy (MRS) changes in NAA/Cr in the AC, pre-SMA, or posterior cingulate (PC). Forty-four (27 male, 17 female) healthy nondemented PD patients and 38 controls (18 male, 20 female) 65 years of age and older were examined using the Unified Parkinson's Disease Rating Scale (UPDRS), Mini-Mental State Examination, Frontal Assessment Battery, and Geriatric Depression Scale. MRS was performed at 1.5 T. Voxels (8 cc; PRESS; TE = 80; TR = 1,600 ms) were placed mid-sagittally. Gray matter and white matter volumes were measured within voxels using SPM2. Spectra were analyzed using LC model to yield NAA/Cr and Cho/Cr. Demographic and cognitive measures did not differ between groups. Motor UPDRS was 17.7 +/- 8.8 for PD. Pre-SMA NAA/Cr was lower in PD (PD: 1.39 +/- 0.17; control: 1.47 +/- 0.16; P = 0.045) and correlated negatively with age (r = 0.39; P = 0.01), but not with UPDRS, disease duration, or dopamine equivalents. AC and PC NAA/Cr and Cho/Cr in any region did not differ (P > 0.05). In conclusion, pre-SMA NAA/Cr was selectively decreased in PD, consistent with neuronal dysfunction. This should be further examined as a biomarker of disease in PD.

Aged↗

PubMed2006

Detection of cerebral degeneration in amyotrophic lateral sclerosis using high-field magnetic resonance spectroscopy.

BACKGROUND: Clinical assessment is insensitive to the degree of cerebral involvement in amyotrophic lateral sclerosis (ALS). Regional brain concentrations N-acetylaspartylglutamate (NAA) plus myo-inositol (Ins), as measured by magnetic resonance spectroscopy, are respectively decreased and increased, suggesting that these compounds may provide a biomarker of the degree of cerebral involvement in ALS. OBJECTIVE: To test the hypothesis that the NAA/Ins ratio may provide an index of cerebral involvement in patients with ALS. DESIGN: High-field (3.0-T) magnetic resonance spectroscopy was performed to determine the NAA/creatine plus phosphocreatine (NAA/Cr), NAA/choline (NAA/Cho), Ins/Cr, and NAA/Ins ratios in the motor cortex. PARTICIPANTS: Seventeen patients with ALS and 15 healthy control subjects were studied. RESULTS: In patients with ALS, the greatest abnormality was a 22% decrease in NAA/Ins (71% sensitivity and 93% specificity, P = .001); Ins/Cr was increased 18% (88% sensitivity and 53% specificity, P = .04), NAA/Cr was decreased 10% (88% sensitivity and 47% specificity, P = .04), and NAA/Cho was decreased 14% (53% sensitivity and 87% specificity, P = .047). Correlation of the ALS Functional Rating Scale with NAA/Ins approached statistical significance (R = 0.43, P = .07). CONCLUSION: The NAA/Ins ratio may provide a meaningful biomarker in ALS given its optimal sensitivity and specificity profile.

Adult↗

PubMed2006

Valvular heart disease in pergolide-treated Parkinson's disease.

BACKGROUND: A 61-year-old woman with Parkinson's disease, receiving pergolide 1.75 mg four times daily, was admitted with progressive dyspnea. METHODS: Investigations revealed mitral and aortic regurgitation. She underwent surgical mitral replacement and aortic repair, but had a post-operative course characterized by repeated bouts of congestive heart failure. RESULTS: Severe tricuspid valve (TV) regurgitation developed within one month after the TV was reported on echocardiography to be relatively normal. Subsequent discontinuation of pergolide was associated with symptomatic improvement. CONCLUSIONS: This case illustrates the severity and rapidity with which cardiac valvular abnormalities can develop in patients receiving pergolide.

Aged↗

PubMed2005

Botulinum toxin injections do not improve freezing of gait in Parkinson disease.

Freezing of gait (FOG) is common in patients with Parkinson disease (PD) and responds poorly to medical treatment. Botulinum toxin A (BTX-A) injections into calf muscles decreased FOG in previous open-label studies. The authors conducted a randomized double-blind placebo-controlled crossover study of BTX-A vs placebo in 12 subjects with PD and FOG. No significant improvement with BTX-A was found using subjective and objective measures.

Aged↗

PubMed2004

Value of an enzymatic assay for the determination of serum ceruloplasmin.

The serum concentration of the copper protein ceruloplasmin has been an important diagnostic indicator of Wilson's disease (WD). It is widely quoted that 95% of people with WD have low serum ceruloplasmin concentrations. Current evidence suggests that a normal serum ceruloplasmin concentration is more common in patients with WD, particularly those with liver disease, perhaps in part because of the routine use of an immunologic assay. This assay might indicate a normal level of ceruloplasmin when the enzymatic activity is lower. Enzymatic activity is the biologically relevant parameter. We compared the immunologic measurement with the enzymatic assessment of oxidase activity in patients with liver or neurologic symptoms of unknown origin in whom WD was considered in the differential diagnosis. Although a strong correlation of ceruloplasmin protein concentration with oxidase activity was observed in controls, this was not the case for these patients. Twelve patients, presenting with various types of hepatic disease, demonstrated a weak correlation between ceruloplasmin protein concentration and oxidase activity. Ten percent of patients with neurologic symptoms ( n = 41) had low ceruloplasmin concentrations and oxidase activity, and another 8% had normal ceruloplasmin concentrations associated with low oxidase activity. Although the enzymatic method is preferred for its biologic relevance, ceruloplasmin analysis is not a reliable diagnostic parameter for the diagnosis of WD in patients with liver disease. An important use of the ceruloplasmin oxidase assay is in the follow-up of patients with WD. Ceruloplasmin oxidase activity was undetectable in sera from patients with WD who were undergoing long-term chelation therapy, suggesting an early sign of copper depletion and a need for subsequent monitoring for symptoms of copper deficiency.

Ceruloplasmin↗

PubMed2003

Treatment of Parkinson's disease.

Parkinson's disease is a progressive neurodegenerative disorder that demands a holistic approach to treatment. Both pharmacologic and nonpharmacologic interventions play an important role in the comprehensive management of this disorder. While levodopa remains the single most effective medication for symptomatic treatment, dopamine agonists are playing an increasingly important role. Motor complications of dopaminergic therapy are a significant issue, particularly in patients with more advanced disease who have been on levodopa for several years. All therapeutic interventions must be tailored to the individual and modified as the disease progresses, with the goal of minimizing significant functional disability as much as possible.

Antiparkinson Agents↗

PubMed2002

Reduction in metabolite transverse relaxation times in amyotrophic lateral sclerosis.

BACKGROUND: Proton magnetic resonance spectroscopy (1H MRS) is used frequently to evaluate normal and pathological states in brain. MRS results are often reported as ratios of peak areas from spectra acquired at a single echo time, primarily for the peaks arising from N-acetyl groups (NA), creatine/phosphocreatine (t-Cr), and choline (Cho). Peak areas, however, are affected not only by metabolite concentration, but also by transverse relaxation times (T(2)). While the ratio approach appears to be valid in normal brain, pathology may affect T(2), thereby leading to misinterpretation of the apparent changes in metabolite ratios. The objective of the present study was to determine if any T(2) changes might affect the apparent metabolite ratio measures, which we have previously reported as being abnormal in amyotrophic lateral sclerosis (ALS). METHODS: 1H MRS data were acquired from the brainstems of ALS and control subjects, for a range of TE times, to calculate T(2) times for each of NA, t-Cr, and Cho. Metabolite ratios were measured experimentally at TE=120 ms and calculated for TE=0 ms, based on measured T(2) values. RESULTS: The T(2)'s for the ALS vs. control group were NA=272+/-10 ms vs. 351+/-58 ms (p<0.01), t-Cr=132+/-17 vs. 184+/-42 ms (p<0.02), and Cho=223+/-55 vs. 245+/-50 ms (p>0.05). The effect of these T(2) changes on metabolite ratios showed both the NA/t-Cr (ALS=0.98+/-0.13, Control=1.44+/-0.10, p<0001) and Cho/t-Cr (ALS=1.01+/-0.12, Control=1.34+/-0.24, p<0.001) ratios to differ significantly between groups. CONCLUSION: This study confirms the presence of significant abnormalities in metabolite concentration in ALS brainstem and the importance of evaluating the effects of metabolite T(2) values when making ratio measurements in disease states.

Amyotrophic Lateral Sclerosis↗

PubMed2002

Multiple gradient echo sequence optimized for rapid, single-scan mapping of R(2)(*) at high B0.

A multiple-gradient-echo sequence is proposed for accurately mapping R(2)(*) in the presence of in-slice macroscopic susceptibility gradients. In-slice signal loss caused by background macroscopic susceptibility gradients is mitigated by combining three successive gradient-echo images whose slice refocus gradients are successively incremented. The optimum incrementation of slice-refocusing gradients was determined by numerical simulation. By repeating further cycles of three images in the same sequence, artifact-compensated data spanning a range of echo times (TEs) was acquired leading to single-scan, R(2) (*) maps that are quantitatively reflective of microscopic field inhomogeneities. The performance of the sequence was demonstrated at 3.0T, first with a doped aqueous phantom, and then on the head of a normal volunteer. That performance is compared quantitatively with previously published work.

Artifacts↗

PubMedDate not supplied

Excessive daytime sleepiness and sudden-onset sleep in Parkinson disease: a survey by the Canadian Movement Disorders Group.

CONTEXT: Somnolence is a recognized adverse effect of dopamine agonists. Two new dopamine agonists, pramipexole and ropinirole, have been reported to cause sudden-onset sleep spells in patients with Parkinson disease (PD) while they were driving. The frequency of these spells and whether driving should be restricted has yet to be established. OBJECTIVE: To determine the frequency of and predictors for sudden-onset sleep and, particularly, episodes of falling asleep while driving among patients with PD. DESIGN, SETTING, AND PARTICIPANTS: Prospective survey conducted between January and April 2000 in 18 clinics directed by members of the Canadian Movement Disorders Group; 638 consecutive highly functional PD patients without dementia were enrolled, of whom 420 were currently drivers. MAIN OUTCOME MEASURES: Excessive daytime sleepiness and sudden-onset sleep as assessed by the Epworth Sleepiness Scale and the Inappropriate Sleep Composite Score. The latter score, designed for this study, addressed falling asleep in unusual circumstances. The 2 scales were combined in 3 separate formats: dozing off, sudden unexpected sleep, and sudden blank spells. RESULTS: Excessive daytime sleepiness was present overall in 327 (51%) of the 638 patients and in 213 (51%) of the 420 drivers. Patients taking a variety of different dopamine agonists had no differences in Epworth sleepiness scores, in the composite score, or in the risk of falling asleep while driving. Sixteen patients (3.8%) had experienced at least 1 episode of sudden onset of sleep while driving (after the diagnosis of PD); in 3 (0.7%), it occurred without warning. The 2 risk factors associated with falling asleep at the wheel were the Epworth Sleepiness Scale score (odds ratio [OR], 1.14; 95% confidence interval [CI], 1.06-1.24) and the Inappropriate Sleep Composite Score (OR, 2.54; 95% CI, 1.76-3.66). A standard Epworth Sleepiness Scale score of 7 or higher predicted 75% of episodes of sleep behind the wheel at a specificity of 50% (exclusion of the question related to driving provided 70% sensitivity and 52% specificity), whereas a score of 1 on the Inappropriate Sleep Composite Score generated a sensitivity of 52% and specificity of 82%. CONCLUSIONS: Excessive daytime sleepiness is common even in patients with PD who are independent and do not have dementia. Sudden-onset sleep without warning is infrequent. The Epworth score has adequate sensitivity for predicting prior episodes of falling asleep while driving and its specificity can be increased by use of the Inappropriate Sleep Composite Score. It is unknown if routinely performing these assessments could be more effective in predicting future risk for these rare sleep attacks. Patients should be warned not to drive if they doze in unusual circumstances.

Aged↗