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PubMedDate not supplied

Music therapy as a treatment method for improving respiratory muscle strength in patients with advanced multiple sclerosis: a pilot study.

Respiratory muscle weakness, predominantly of the expiratory muscles, is characteristic of individuals with advanced multiple sclerosis and can result in difficulty in clearing secretions and repeated episodes of pneumonia. This pilot study evaluated the effectiveness of music therapy in strengthening respiratory muscles through an emphasis on diaphragmatic breathing and coordination of breath and speech. Twenty patients were randomly assigned to one of two groups: one that received music therapy or one that attended music appreciation sessions. Participants' inspiratory and expiratory muscle strength was measured by testing mouth pressure before and after the intervention. The experimental group showed some improvement in terms of expiratory muscle strength, in contrast to the control group, which showed deterioration. The results were not statistically significant, however. Patients in both groups exhibited considerable weakness in their expiratory muscles, and results for 79% of the participants were below 30% of the predicted values. Variability, a major confounding factor that resulted in reduced statistical power, led the investigators to suggest an intercenter collaboration to amass sufficient numbers of patients for a future study. Early manifestation of respiratory muscle weakness warrants inclusion of respiratory muscle testing in examination protocols and early intervention efforts.

Adult↗
PubMed2004

Experimental assessment of new stent technologies: validation of a comparative paired rabbit iliac artery study model.

Preventing coronary in-stent restenosis is a major challenge for physicians and industry. To assess new stent technologies, a comparative paired iliac artery model in rabbits is proposed. One tubular stent was implanted in each external iliac artery in 12 rabbits (i.e., 24 stents). An artery overdilatation level of 20% was strictly observed. Restenosis was examined at 30 days by angiography, intravascular ultrasound (IVUS) examination, and histomorphometry. On quantitative angiography, the mean loss of angiographic diameter was 9.8 +/- 4.4% in the right as compared to 9.3 +/- 55% in the left artery (p = 0.75). On IVUS, the volume of intrastent neointimal proliferation was 26.6 +/- 4.9 mm(3) in the right and 25.8 +/- 3.5 mm(3) in the left artery (p = 0.58). In histomorphometry, the neointimal proliferation area was 0.78 +/- 17 mm(2) in the right and 0.76 +/- 0.17 mm(2) in the left artery (p = 0.87). Intrastent neointimal proliferation was comparable between the left and right arteries of all rabbits. The model has three main advantages: (1) arterial dilatation and thus arterial wall aggression are controlled, (2) pairing makes each animal its own control subject, and (3) the statistical power for comparative testing is maximized. The model enables the effect of a new drug-delivery device to be assessed.

Animals↗
PubMed1995

Determinants of bone mineral density in older men.

Osteoporosis is a significant health problem and contributor to disability and premature mortality among older men. Incidence rates for hip fracture have stabilized in women, but continue to increase in men. A major risk factor for hip fracture is bone mineral density level. The determinants of bone mineral density (BMD) are well defined in women, but not in men. The primary goal of the current research was to increase our understanding of the determinants of BMD of the proximal femur in a large community-based sample of older male volunteers. Eligibility requirements included age of 50 years or older, ambulatory, and not having undergone a bilateral hip replacement. Five hundred twenty-three men, mean mean age 66.6 years, met all eligibility requirements and participated in the Study of Osteoporotic Risk in Men or STORM. Information on demographics, medical history, anthropometry, leisure-time and occupational physical activity, muscular strength, cigarette smoking, alcohol consumption, dietary calcium intake, and medication use (thiazide diuretics and glucocorticoids) were obtained by questionnaire, interview, and examination, BMD of the proximal femur (femoral neck, greater trochanter, and Ward's triangle) was measured by dual-energy X-ray absorptiometry using the Hologic QDR-1000 and QDR-2000. The cross-sectional determinants of BMD included age, blond hair color, current body weight, thiazide diuretic use, historical physical activity, and quadriceps strength. Several variables commonly thought to be determinants of BMD were not related to BMD in this population of older men, including current cigarette smoking, alcohol consumption, current leisure-time physical activity, dietary calcium intake, vitamin D use, and caffeine intake. However, failure to find associations among BMD and some of the potential determinants may be due to lack of statistical power. Identification of the determinants of BMD could lead to the development of interventions aimed at maximizing BMD in men and could potentially decrease the risk of hip fractures.

Absorptiometry, Photon↗
PubMed2006

A scoring system based on the expression of six surface molecules allows the identification of three prognostic risk groups in B-cell chronic lymphocytic leukemia.

We have previously identified 12 surface antigens whose differential expression represented the signature of B-cell chronic lymphocytic leukemia (B-CLL) subsets with different prognosis. In the present study, expression data for these antigens, as determined in 137 B-CLL cases, all with survivals, were utilized to devise a comprehensive immunophenotypic scoring system of prognostic relevance for B-CLL patients. In particular, univariate z score was employed to identify the markers with greater prognostic impact, while maximally selected log-rank statistics were chosen to define the optimal cut-off points capable to split patients into two groups with different survivals. A weighted immunophenotypic scoring system was developed by integrating results from these analyses. Six antigens were selected: three positive prognosticators (CD62L, CD54, CD49c) and three negative prognosticators (CD49d, CD38, CD79b), with cut-off values ranging from 30% to 50% of positive cells. By weighing the expression of each marker according to its statistical power, a complete scoring system, with point values comprised between 0 (complete absence of phenotypic conditions associated with good prognosis) and 9 (all the phenotypic conditions associated with good prognosis fulfilled), allowed to split the whole set of B-CLL patients, into three distinctive prognostic groups (P = 4.78 x 10(-11)) with high- (score 0-3), intermediate- (score 4-6), and low- (score 7-9) risk of death. The three risk groups showed different distribution of cases as for Rai's stages, IgVH mutations, and ZAP-70 expression. The proposed immunophenotypic scoring system may be an additional useful tool in routine diagnostic/prognostic procedures for B-CLL.

ADP-ribosyl Cyclase 1↗
PubMed2001

Improved mapping of pharmacologically induced neuronal activation using the IRON technique with superparamagnetic blood pool agents.

The use of functional magnetic resonance imaging (fMRI) techniques for evaluation of pharmacologic stimuli has great potential for understanding neurotransmitter dynamics for a number of brain disorders, such as drug abuse, schizophrenia, epilepsy, or neurodegeneration. Unfortunately, blood oxygenation level-dependent (BOLD) imaging at common fields strengths, such as 1.5 or 3 T, has very low sensitivity and contrast-to-noise ratios (CNRs). We demonstrate here the utility of using an intravascular superparamagnetic iron oxide contrast agent with a long plasma half-life for evaluation of hemodynamic changes related to dopaminergic stimuli using amphetamine or the cocaine analog 2beta-carbomethoxy-3beta-(4-fluorophenyl)tropane (CFT). We refer to this technique as increased relaxation with iron oxide nanoparticles (IRON). Results obtained here show that even at field strengths as high as 4.7 T, one can obtain increases in CNR by factors of 2-3 over BOLD imaging that lead to greater than an order of magnitude increase in statistical power with greatly increased sensitivity to hemodynamic changes in brain regions difficult to observe using BOLD imaging. Furthermore, use of the intravascular contrast agent allows for a meaningful physiologic parameter to be measured (relative cerebral blood volume (rCBV)), compared to conventional BOLD imaging.

Animals↗
PubMed2006

Comparative study into the robustness of compartmental modeling and model-free analysis in DCE-MRI studies.

PURPOSE: To evaluate and compare the reproducibility of the preferred phenomenological parameter IAUC60 (initial area under the time-concentration curve [IAUC] defined over the first 60 seconds postenhancement) with the preferred modeling parameter (K(trans)), as derived using two simple models, in abdominal and cerebral data collected in typical Phase I clinical trial conditions. MATERIALS AND METHODS: Dynamic contrast enhanced MRI (DCE-MRI) time series were acquired at two imaging centers from a group of patients with abdominal tumors and a group with gliomas. At both imaging centers, precontrast T1 was calculated using a variable flip angle three-dimensional spoiled gradient echo acquisition that was used to quantify tissue contrast agent concentration, allowing voxelwise definition of summary DCE-MRI parameters. RESULTS: A comparison of reproducibility showed that there was no statistically significant difference in reproducibility between IAUC60 and K(trans), although there was a trend towards better reproducibility for K(trans) (P = 0.0782). The 95% confidence intervals (CIs) for individual changes showed that for IAUC60 and K(trans), changes in excess of 47% and 31%, respectively, are outside the range of normal variability. CONCLUSION: Although modeling is more complex and more computationally intensive than an IAUC parameterization, our data suggest this approach to be preferable to a model-free approach since it provides greater physiological insight without a reduction in statistical power for Phase I/II clinical drug trials.

Abdominal Neoplasms↗
PubMed1994

Technique for in vivo measurement of the three-dimensional kinematics and laxity characteristics of the ankle joint complex.

We introduce here a technique to measure the three-dimensional kinematics and laxity characteristics of the ankle joint complex in vivo. The system consists of an optoelectric, kinematic data acquisition system that is used to measure the motion of the ankle joint complex in response to controlled moments applied through a system of pneumatic actuators. As a first step toward development of the method into a quantitative diagnostic tool for injuries of ankle ligaments, we addressed the following questions: (a) What is the reliability for measurement of range of motion and laxity of the ankle joint complex? (b) Are there significant differences in laxity between the left and right joints of a healthy individual? and (c) Are there significant differences in laxity of the ankle joint complex between men and women? To answer these questions, we performed repeated measures of range of motion and laxity of paired ankles in a population of 18 healthy young individuals. The high intraclass correlation coefficients obtained from the statistical analysis indicate that the new experimental system is highly reliable in measurement of total range of motion and total laxity of the ankle joint complex. We further concluded that, within the statistical power available in our experimental design, there are no significant differences in either range of motion or laxity between left and right ankles of healthy individuals or between men and women.

Adult↗
PubMed1998

Method to assess in vivo knee stability longitudinally in an animal model of ligament injury.

The purpose of this study was to develop a method to prospectively quantify passive knee stability in an animal model of joint injury over time. Knee stability is defined here as the amount of translation or rotation of the tibia relative to the femur for a given application of force or moment, respectively. Five animals that had undergone transection of the anterior cruciate ligament and three control animals that had undergone a sham operation were anaesthetized and positioned in a stereotaxic frame. Motion of the tibia relative to the femur was quantified with use of reflective markers secured to modified bone pins and a three-dimensional motion analysis system. External forces and moments in the transverse plane of the tibia were measured with use of force transducers based on a strain-gauge design. Longitudinal measurements of knee stability were made before either sham surgery (control animals) or transection of the ligament (experimental animals), immediately after surgery, and at 2 and 4 months after transection. The results showed that the animals tolerated the procedures well and that systematic measurements could be obtained. The method described here has the practical advantage over cross-sectional experimental designs in that the number of subjects can be decreased while maintaining statistical power and has the further conceptual advantage that individual changes can be accounted for over time.

Animals↗
PubMed2004

Influence of feeding and analytical method on the bioequivalence of a racemic drug undergoing enantioselective enterohepatic recycling.

Two crossover bioequivalence trials of an enantioselectively enterohepatic recycled drug, carprofen, were conducted in dogs with the same racemic oral formulation to determine: (i) the influence of feeding patterns, and (ii) the effect of the analytical method (enantioselective vs non-enantioselective) on the statistical power of the trials. The first trial was conducted with a standard feeding protocol and the second with a special feeding protocol selected to ensure constant biliary flow into the duodenum. Using a non-enantioselective technique, 90% confidence intervals provided conclusions of bioequivalence in 100% of the cases for both area under the plasma concentration versus time curve (AUC) and maximum plasma drug concentration (Cmax) with the special feeding protocol, but only 50% for AUC and 13% for Cmax with the standard feeding protocol, suggesting that a feeding pattern that diminishes plasma drug concentration rebound for an enterohepatically recycled drug increases the power of a bioequivalence trial. Whatever the feeding protocol, an enantioselective method decreased the power of the trials for AUC but increased the power of the trials for Cmax. For an enterohepatically recycled drug, feeding pattern can influence the power of a bioequivalence trial, and the analytical technique that provides the greatest power depends on the assessed bioequivalence parameter and the feeding pattern.

Animals↗
PubMed2005

Cytokine gene polymorphisms and acute liver graft rejection: a meta-analysis.

In the field of liver transplantation, 7 reports have been published investigating the association between polymorphisms in cytokine genes and the occurrence of acute rejection in liver graft recipients. However, most of the individual studies lack the statistical power to detect a small-to-moderate effect of cytokine gene polymorphisms on the acute rejection rate. To overcome this problem, we performed a quantitative meta-analysis of 7 gene-association studies that were comparable with regard to definition of acute rejection and the type of immunosuppression used. In the overall analysis, the interleukin (IL)-10 polymorphism at position -1082 was identified as a genetic risk factor for acute liver graft rejection; liver transplant recipients carrying the IL-10 -1082.A allele displayed a lower rejection rate (common odds ratio [OR], .6; 95% confidence interval [CI], .4-.9). For the tumor necrosis factor (TNF)-A -308 polymorphism, a common OR could not be calculated due to significant heterogeneity of ORs between the studies (mean OR, 1.4; 95% CI, .8-2.6). No associations were found between acute liver graft rejection and single nucleotide polymorphisms in the IL-6 (position -174) and transforming growth factor (TGF)-beta1 (positions +869 and +915) genes. In conclusion, results from this meta-analysis suggest a role for the IL-10 -1082 polymorphism in human liver graft rejection.

Acute Disease↗
PubMed2004

A "cure" for Parkinson's disease: can neuroprotection be proven with current trial designs?

Current medical and surgical therapies for Parkinson's disease provide symptomatic control of motor impairments rather than slowing or halting the progression of the disease. Previous clinical trials examining drugs such as dopamine agonists and selegiline for neuroprotective effects used "surrogate" outcomes, including clinical measures (rating scales, time to require levodopa), neuroimaging techniques (beta-CIT single photon emission computed tomography; fluorodopa positron emission tomography), and mortality tracking. These studies failed to provide conclusive results because of design faults such as failing to control for symptomatic effects, small sample size, and not accounting for the possible effects of drugs on radionuclide tracer handling. Lessons must be learned from these failed neuroprotection trials. This review summarises the problems with previous neuroprotection studies and makes recommendations for future trial design. It is concluded that the primary outcome of explanatory trials should continue to be clinical measures such as the Unified Parkinson's Disease Rating Scale (UPDRS). It should be assumed that all agents have a symptomatic effect, which necessitates evaluation after a prolonged drug washout period. To achieve the evaluation after a prolonged drug washout period more effectively, trials must be performed in early disease and over a short period (6-12 months) so that symptomatic therapy is not required. To achieve adequate statistical power, these trials will need to include thousands of patients. Radionuclide imaging can only be used in such trials after considerable methodological work has been performed to establish its validity and reliability. To be affordable, such large explanatory trials need more streamlined designs with fewer hospital visits, fewer outcome measures, and rationalised safety monitoring. The clinical effectiveness of promising compounds from explanatory trials will need to be established in large long-term pragmatic trials using outcome measures such as quality of life, cost-effectiveness, and mortality. Such pragmatic trials could be continuations of the explanatory trials: after the primary outcome of the explanatory study (e.g., UPDRS) has been reported in an interim analysis, the trial could be continued for a further 5 to 10 years to report on quality of life and health economics outcomes.

Antiparkinson Agents↗
PubMed1994

Factors influencing the amplitude and frequency of essential tremor.

Quantitative electromyography (EMG) and triaxial accelerometry were used to measure hand tremor, finger tremor, and forearm motor unit activity in 36 men and 23 women with essential tremor. Hand tremor was studied with and without 300-g mass loading. Tremor and EMG were recorded twice, with a 3-min rest interval, to assess the spontaneous intertrial variability in tremor amplitude, frequency, and motor unit entrainment. In general, the minimum detectable differences in tremor amplitude, frequency, and motor unit entrainment were roughly 30%, 5%, and 10% of the initial sample means, respectively, assuming a sample size of 30 patients, a statistical power of 0.9, and a significance level of 0.05. Linear regression analyses were performed to test the hypotheses that (a) there is an age-associated decrease in tremor frequency that is independent of symptom duration and (b) tremor frequency and motor unit entrainment make independent contributions to tremor amplitude. Our data supported both hypotheses.

Adolescent↗
PubMed2000

Assessing state parity legislation*

The temptation is great, but premature, to conclude from the Sturm study that parity mandates had no effect on access and insurance coverage for the mentally ill. The study lacks statistical power for those directly covered by the mandates, and it is unlikely adequate power exists for those only indirectly affected. The inclusion of the uninsured, Medicaid enrollees, and privately covered individuals not subject to the mandates, and the imprecise outcome measures, increase the likelihood that other factors dominate parity. The timing of implementation in some states is also problematic. But Sturm asks the right questions and future waves of the Healthcare for Communities survey and other data will be better able to address them.arkets and policies.

Journal Article↗
PubMed2001

Repetition time in echo planar functional MRI.

To date, surprisingly little attention has been directed toward determining the optimum TR in a functional imaging experiment. A survey of the literature reveals a wide range of TRs, but little justification for a specific TR. Long-TR functional imaging experiments provide maximum signal-to-noise ratio (SNR) in the raw images; allow for the collection of a large number of slice locations; and decrease the size of the data set acquired, simplifying storage and handling. This work, however, demonstrates that long-TR imaging sacrifices statistical power when the paradigm timing is held fixed. That is, for a fixed-run duration consisting of multiple activation/control blocks, shorter TR acquisitions (on the order of 1000 ms) provide better discrimination between the activated and nonactivated brain tissue regions than do long-TR acquisitions (on the order of 4000 ms). Results are shown for modeling the functional imaging experiment and for three different paradigms performed on normal subjects.

Adult↗
PubMed1993

Assessment of changes in murine tumor oxygenation in response to nicotinamide using 19F NMR relaxometry of a perfluorocarbon emulsion.

The oxygen dependencies of the 19F NMR spin-lattice relaxation rates (R1 = 1/T1) of a perfluorocarbon emulsion sequestered in a murine tumor model has been used to evaluate nicotinamide, a radiosensitizer believed to act through enhanced tissue oxygenation. Fluorine-19 NMR spectroscopic measurements from solid Radiation-Induced Fibrosarcoma (RIF-1) tumors in C3H mice showed a statistically significant improvement in tumor pO2 for a Nicotinamide-treated group, with a delta pO2 = 4.7 +/- 3 torr ( = mm Hg) (Mean +/- SEM) at t = 60 min (P < .01), and 4.5 +/- 3 at t = 70 min post intraperitoneal injection (P < 0.02) as compared with saline-treated Controls, while several other time points for which t > 30 min were significant at the P < 0.05 level. Both groups had n = 10, and the statistics were based on Student's one-tailed group t test. By comparison, in another study group where breathing gas was switched from air to 100% O2, a statistically insignificant increase of 2 torr was realized in tumor pO2 (n = 9). The maximal treatment effect occurs at a delay of 60 to 70 min, consistent with results obtained by other investigators using radiobiology techniques. Fluorine-19 spectroscopic relaxometry can measure therapeutically meaningful changes in in vivo tumor pO2 and represents an improvement in expenditures of time, animal resources, and statistical power over conventional radiobiological methods.

Animals↗
PubMed2005

Modeling and suppression of respiration-related physiological noise in echo-planar functional magnetic resonance imaging using global and one-dimensional navigator echo correction.

A major source of noise in functional magnetic resonance imaging (fMRI) arises from modulations in the local magnetic field in the head due to motion of the subject's chest through the respiratory cycle, and this physiologic noise can nullify the gains in statistical power expected by the use of higher magnetic fields for fMRI. In particular, fMRI data acquired using echo-planar imaging (EPI) are very sensitive to these spatially and temporally varying respiration-induced frequency offsets. In this study, accurate 3D magnetic field maps in the head were measured and used to determine the frequency offsets at the two extremes of the respiratory cycle. From these maps, spatially dependent frequency variations from about -1.0 Hz to +1.5 Hz were measured in the brain through the respiratory cycle. Simulations of a typical axial EPI fMRI experiment acquired in the presence of this measured field variation were performed, demonstrating regional image intensity variations between 1 and 5% in single pixel time series. The inadequacy of either global or 1D navigator echo corrections to measure and suppress respiratory-induced noise in fMRI time series is demonstrated. The nature of the spatial variations observed suggests that 2D approaches should be considered.

Brain Mapping↗
PubMed2006

Dependence of gradient-echo and spin-echo BOLD fMRI at 4 T on diffusion weighting.

Diffusion weighting and spin-echo (SE) acquisitions can be used to help improve the spatial localization of BOLD fMRI at the cost of reduced acquisition rates and lower signal-to-noise ratio (SNR). To evaluate these costs, SE and gradient-echo (GE) data were acquired at 4 T at five diffusion weightings ranging from b = 0 to 1110 s/mm(2) using a robust visual stimulus. The data showed reduced functional contrast when diffusion weighting was applied. As the amount of diffusion weighting increased, the functional contrast initially dropped sharply, and then remained relatively constant for diffusion weightings above 15 s/mm(2) for SE and 30 s/mm(2) for GE data. GE functional BOLD contrast was attenuated to 94.0 +/- 10.1, 87.6 +/- 12.2, 86.4 +/- 8.8 and 83.3 +/- 20.6% of the non-diffusion-weighted GE contrast for diffusion weightings of 15, 30, 200 and 1,110 s/mm(2). The non-diffusion-weighted SE contrast greatly reduced to 19.3 +/- 3.3% of the non-diffusion-weighted GE contrast, demonstrating the large activation attenuation of a SE acquisition. The SE contrast was further reduced to 10.0 +/- 3.6, 9.0 +/- 2.5 and 8.6 +/- 2.0% of the non-diffusion-weighted GE contrast for the 15, 30 and 200 s/mm(2) diffusion-weighted data. These results suggest that only a small amount of diffusion weighting is necessary to suppress the vascular contribution and spin-echo imaging should only be used if there is adequate statistical power available or accurate localization is critical.

Adult↗
PubMed2006

Differential attrition in a caregiver skill training trial.

Participant attrition in randomized trials can reduce statistical power and bias outcomes. However, elective withdrawals are seldom discussed in trial reports. We examined factors associated with elective withdrawals for the first 131 Alzheimer's disease (AD) and Parkinson's disease (PD) caregiver participants that entered Project ASSIST (Assistance, Support and Self-health Initiated through Skill Training), an on-going trial of caregiver skill training interventions. After 20 months of recruitment, 14 (11%) of the 131 ASSIST participants had electively withdrawn before completing the final assessment. Survival analysis demonstrated AD caregivers and non-spousal caregivers dropped out earlier than PD and spousal caregivers, even after controlling for selected baseline covariates. Findings suggest caregiver trial contact strategies may need to be tailored to retain different caregiver groups.

Adaptation, Psychological↗