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Biomedical subjects

R Coleman

Publications and source records attributed to R Coleman.

At least 397 records · Page 22Linked to original sources
PubMedDate not supplied

Radiotherapy versus single-dose carboplatin in adjuvant treatment of stage I seminoma: a randomised trial.

BACKGROUND: Adjuvant radiotherapy is effective treatment for stage I seminoma, but is associated with a risk of late non-germ-cell cancer and cardiovascular events. After good results in initial studies with one injection of carboplatin, we undertook a large randomised trial to compare the approaches of radiotherapy with chemotherapy in seminoma treatment. METHODS: Between 1996 and 2001, 1477 patients from 70 hospitals in 14 countries were randomly assigned to receive radiotherapy (para-aortic strip or dog-leg field; n=904) or one injection of carboplatin (n=573; dose based on the formula 7x[glomerular filtration rate+25] mg), at two trial centres in the UK and Belgium. The primary outcome measure was the relapse-free rate, with the trial powered to exclude absolute differences in 2-year rates of more than 3%. Analysis was by intention to treat and per protocol. This trial has been assigned the International Standard Randomised Controlled Trial Number ISRCTN27163214. FINDINGS: 885 and 560 patients received radiotherapy and carboplatin, respectively. With a median follow-up of 4 years (IQR 3.0-4.9), relapse-free survival rates for radiotherapy and carboplatin were similar (96.7% [95% CI 95.3-97.7] vs 97.7% [96.0-98.6] at 2 years; 95.9% [94.4-97.1] vs 94.8% [92.5-96.4] at 3 years, respectively; hazard ratio 1.28 [90% CI 0.85-1.93], p=0.32). At 2 years' follow-up, the absolute differences in relapse-free rates (radiotherapy-chemotherapy) were -1.0% (90% CI -2.5 to 0.5) by direct comparison of proportions, and 0.9% (-0.5 to 3.0) by a hazard-ratio-based approach. Patients given carboplatin were less lethargic and less likely to take time off work than those given radiotherapy. New, second primary testicular germ-cell tumours were reported in ten patients allocated irradiation (all after para-aortic strip field) and two allocated carboplatin (5-year event rate 1.96% [95% CI 1.0-3.8] vs 0.54% [0.1-2.1], p=0.04). One seminoma-related death occurred after radiotherapy and none after carboplatin. INTERPRETATION: This trial has shown the non-inferiority of carboplatin to radiotherapy in the treatment of stage I seminoma. Although the absence of disease-related deaths and preliminary data indicating fewer second primary testicular germ-cell tumours favour carboplatin use, these findings need to be confirmed beyond 4 years' follow-up.

Adult↗
PubMedDate not supplied

Correlation and quantification of relative 2-dimensional projected vertebral endplate z-axis rotations with 3-dimensional y-axis vertebral rotations and focal spot elevations.

BACKGROUND: The use of lines erected on the vertebral endplates of the anterior-to-posterior radiograph to assess z-axis vertebral rotation is a common clinical practice. OBJECTIVE: To quantify the projection/distortion error of lateral flexion (z-axis rotation) measurement, which results from actual axial (y-axis) rotation and changes in focal spot elevation, on AP radiographs. STUDY DESIGN: A 3-dimensional model of a 4th and 5th lumbar vertebrae was constructed with a computer. The angle between the projected inferior vertebral endplate of the 4th lumbar vertebra, and the projected superior vertebral endplate of the 5th lumbar vertebra was measured. This was done for combinations of 0, 7, 14, and 21 degrees of axial (-y-axis) rotation with 0, 15, and 30 cm of elevation of a modeled focal spot. RESULTS: An angle was produced between the projected inferior 4th lumbar vertebral endplate and the projected superior 5th lumbar vertebral endplate as a result of y-axis rotation of the 3-dimensional model. Increasing magnitudes of y-axis rotation and increasing focal spot elevation produced a lack of confidence in this measurement. CONCLUSION: In a clinical setting, limited ranges of y-axis rotation have little significant effect on the accuracy of this measurement. Increases in y-axis rotation and focal spot elevation can affect measurement accuracy.

Computer-Aided Design↗
PubMedDate not supplied

Simultaneous reconstruction, segmentation, and edge enhancement of relatively piecewise continuous images with intensity-level information.

A multinomial image model is proposed which uses intensity-level information for reconstruction of contiguous image regions. The intensity-level information assumes that image intensities are relatively constant within contiguous regions over the image-pixel array and that intensity levels of these regions are determined either empirically or theoretically by information criteria. These conditions may be valid, for example, for cardiac blood-pool imaging, where the intensity levels (or radionuclide activities) of myocardium, blood-pool, and background regions are distinct and the activities within each region of muscle, blood, or background are relatively uniform. To test the model, a mathematical phantom over a 64 x 64 array was constructed. The phantom had three contiguous regions. Each region had a different intensity level. Measurements from the phantom were simulated using an emission-tomography geometry. Fifty projections were generated over 180 degrees, with 64 equally spaced parallel rays per projection. Projection data were randomized to contain Poisson noise. Image reconstructions were performed using an iterative maximum a posteriori probability procedure. The contiguous regions corresponding to the three intensity levels were automatically segmented. Simultaneously, the edges of the regions were sharpened. Noise in the reconstructed images was significantly suppressed. Convergence of the iterative procedure to the phantom was observed. Compared with maximum likelihood and filtered-backprojection approaches, the results obtained using the maximum a posteriori probability with the intensity-level information demonstrated qualitative and quantitative improvement in localizing the regions of varying intensities.

Algorithms↗
PubMedDate not supplied

Muscle strength and mass of lower extremities in relation to functional abilities in elderly adults.

BACKGROUND: Functional and physiological declines in advancing age may be significant limiting factors in reduced physical activity. Sarcopenia of aging, as a normative process or disease, cannot entirely explain reduced physical activity in the elderly. OBJECTIVE: The purpose of the study was to investigate the relationship between muscle loss and reduction in functional abilities in elderly adults and also to determine whether an exercise program can improve functional performance and muscle quality. METHODS: Anthropometric measurements and sensorimotor testing were conducted on 28 volunteers (12 men and 16 women, 82.7 +/- 2.4 years of age) who were permanent residents in a skilled nursing facility. Twenty-nine elderly adults (79.3 +/- 3.5 years of age) served as a control, nonexercising group. Anthropometric measurements included: weight, height, body fat, and thigh circumference. The muscle strength was tested with a medical isokinetic system. We assessed two sensorimotor functions including a 'timed up-and-go' test and a 3-min distance walking test. The institutionalized participants undertook an exercise training program lasting 12 weeks. RESULTS: No significant changes were observed in thigh circumference, body weight, or percentage of body fat in either gender as a result of the exercise training. An improvement in muscle strength was noticed in 82% of the relatively younger group (79-83 years of age) under a slow voluntary contraction at 60 degrees /s (p < 0.05). Post-training results showed a significant improvement in performance in the two sensorimotor tests (p < 0.05). The correlation coefficients between muscle strength and functional ability were weak: r = 0.60 and r = 0. 57 for males and females, respectively. CONCLUSIONS: This study confirmed the positive effects of an exercise program on functional performance in older adults. The improvement in functional abilities did not correlate with muscle strength, body weight, or body fat.

Adipose Tissue↗