Improvements in mobility for people with disabilities.
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Persons with Disabilities↗
Biomedical subjects
R A Cooper
Publications and source records attributed to R A Cooper.
Evaluation of a pushrim-activated, power-assisted wheelchair.
OBJECTIVE: To evaluate a novel pushrim-activated, power-assisted wheelchair (PAPAW) for compliance with wheelchair standards, metabolic energy cost during propulsion, and ergonomics during selected activities of daily living (ADLs). DESIGN: A 3-phase study, the second and third of which were repeated-measures designs. SETTING: A rehabilitation engineering center within a Veterans Affairs medical center. PATIENTS: Eleven full-time, community-dwelling, manual wheelchair users (4 women, 6 men) with spinal cord injuries or multiple sclerosis. INTERVENTIONS: Phase 1: Compliance testing, with a test dummy, in accordance with the wheelchair standards of the American National Standards Institute and the Rehabilitation Engineering and Assistive Technology Society of North America. Phase 2: Metabolic energy consumption testing-at 2 speeds and 3 resistance levels-in subjects' manual wheelchair and the PAPAW. Phase 3: Evaluation of ability to perform ADLs and ergonomics of the PAPAW compared with the subjects personal wheelchair. MAIN OUTCOME MEASURES: Phase 1: The PAPAW's static stability, static strength, impact strength, fatigue strength, environmental response, obstacle climbing ability, range, maximum speed, and braking distance. Phase 2: Subjects' oxygen consumption per minute, minute ventilation, and heart rate during different speeds and workloads with a PAPAW and their own wheelchairs. Phase 3: Subject ratings of perceived comfort and basic ergonomics while performing selected ADLs. Completion time, stroke frequency, and heart rate during each ADL. RESULTS: Phase 1: The PAPAW was found to be in compliance with wheelchair standards. Phase 2: With the PAPAW, the user had a significantly lower oxygen consumption (&Vdot;O(2)mL/min: p <.0001; &Vdot;O(2)mL/kg x min: p <.0001) and heart rate (p <.0001) when compared with a manual wheelchair at different speeds. Phase 3: The PAPAW had a significantly higher mean ergonomic evaluation (p <.01) than the subjects' personal wheelchairs. The results of comparing the ratings of the car transfer between the PAPAW and the subjects' personal wheelchair showed a significant difference in the task of taking the wheels off (p <.001) and putting the wheels back on (p =.001), with the PAPAW receiving lower ratings. CONCLUSION: This study indicated that the PAPAW is compliant with wheelchair standards, reduces the energy demand placed on the user during propulsion, and that subjects rated its ergonomics favorably when compared with their personal wheelchair. PAPAWs may provide manual wheelchairs with a less physiologically stressful means of mobility with few adaptations to the vehicle or home environment.
Adult↗
Comparison of fatigue life for 3 types of manual wheelchairs.
OBJECTIVES: To examine 3 types of manual wheelchairs-ultralight wheelchairs (UWs), lightweight wheelchairs (LWs), and depot wheelchairs (DWs)-and to compare the fatigue life between the wheelchair types. DESIGN: A database of different manual wheelchairs tested according to the International Organization for Standardization (ISO). Fatigue life was determined by using standards that define methods accepted internationally using double-drum and curb-drop testing equipment. SETTING: A rehabilitation engineering center. SPECIMENS: Sixty-one manual wheelchairs: 25 DWs, 22 UWs, and 14 LWs. MAIN OUTCOME MEASURES: Wheelchairs were examined for differences in fatigue life based on equivalent cycles. Unique survival curves were fit and compared for each wheelchair type. RESULTS: The UWs lasted the longest, with a mean of 309,362 equivalent cycles. The DWs faired the worst, with a mean of 117,210 equivalent cycles. The Kaplan-Meier survival curves were significantly different (p < .001), with the UWs having the longest fatigue life. CONCLUSION: Fatigue life for UWs is significantly greater (p < .05) than LWs and DWs, indicating wheelchairs differ in durability.
Equipment Failure↗
Patterns of relapse following radiotherapy for stage I seminoma of the testis: implications for follow-up.
A retrospective review was undertaken of 409 consecutive patients treated with adjuvant radiotherapy for Stage I seminoma between 1988 and 1997. A total of 339 men were treated to a volume encompassing the para-aortic nodes and 70 were treated with extended field radiotherapy. The patients were followed up within oncology clinics adhering to a standard protocol of clinical examination, chest radiography and measurement of serum marker levels. No routine computed tomographic (CT) scans were carried out. At a median follow-up of 57 months, 13 patients have relapsed, giving a recurrence-free rate of 97.2% at 3 years and 96.8% at 5 years. Of these, eight (62%) were detected at routine appointments and five (38%) requested early appointments. Chest radiography (2/5) and serum marker levels (3/5) identified disease in asymptomatic patients. Eight patients (62%) had raised markers at relapse, including two with normal serum markers at original presentation. The median size of pelvic node recurrences in the para-aortic-treated group was 7.3 cm (2.8-13 cm). Four patients have developed second testicular primaries: three were detected at routine appointments and one patient had requested an early appointment. We conclude that regular follow-up with serum marker estimations and chest radiography is sufficient to detect recurrence at an early stage and that our policy of no routine CT scanning has been shown to give acceptable results.
Biomarkers, Tumor↗
Healing of an MRSA-colonized, hydroxyurea-induced leg ulcer with honey.
BACKGROUND: With the everincreasing emergence of antibiotic-resistant pathogens, in particular methicillin-resistant Staphylococcus aureus (MRSA) in leg ulcers, a means of reducing the bacterial bioburden of such ulcers, other than by the use of either topical or systemic antibiotics, is urgently required. METHODS: We report the case of an immunosuppressed patient who developed a hydroxyurea-induced leg ulcer with subclinical MRSA infection which was subsequently treated with topical application of manuka honey, without cessation of hydroxyurea or cyclosporin. RESULTS: MRSA was eradicated from the ulcer and rapid healing was successfully achieved. CONCLUSION: Honey is recognized to have antibacterial properties, and can also promote effective wound healing. A traditional therapy, therefore, appears to have enormous potential in solving new problems.
Administration, Topical↗
Comparison of three different models to represent the wrist during wheelchair propulsion.
Due to the high incidence of secondary wrist injury among manual wheelchair users, recent emphasis has been placed on the investigation of wheelchair propulsion biomechanics. Accurate representation of wrist activity during wheelchair propulsion may help to elucidate the mechanisms contributing to the development of wrist injuries. Unfortunately, no consensual wrist biomechanical model has been established. In order to determine if different methodologies obtain similar results, this investigation created and compared three different wrist models: 1) a fixed joint center placed between the styloids (midstyloid joint center); 2) a joint center with 2 degrees of freedom computed from de Leva's joint center data; and 3) a floating joint center. Results indicate that wrist flexion and extension angles are highly consistent between models, however, radial and ulnar deviation angles vary considerably. Mean maximum right flexion angles were found to be 3.5 degrees, 2.2 degrees, and 5.0 degrees for the midstyloid, de Leva, and floating joint center models, respectively. Extension angles were 22.3 degrees, 23.6 degrees, and 23.6 degrees, respectively. Mean maximum right radial deviation angles for the midstyloid, de Leva, and floating joint center models were 26.0 degrees, 26.9 degrees, and 45.1 degrees, respectively, and ulnar deviation angles were found to be 30.5 degrees, 38.8 degrees, and 10.2 degrees, respectively. This information is useful when comparing kinematic studies and further supports the need for consensual methodology.
Biomechanical Phenomena↗
Health care workforce for the twenty-first century: the impact of nonphysician clinicians.
For many years, nonphysician clinicians (NPCs) have participated in the care of patients. However, their numbers were small and their licensed prerogatives were narrow. Over the past decade, these characteristics have changed in three important ways. First, training in many of the NPC disciplines has increased substantially, and the growth of these disciplines is accelerating. Second, state laws and regulations have expanded both the practice prerogatives of NPCs and their autonomy from physician supervision. Third, payers have increased their access to reimbursement. As a consequence, NPCs are undertaking many elements of care that previously were provided by physicians. Their participation is generally cost-effective and is met with a high degree of patient satisfaction. This presents both opportunities and challenges to physicians as they forge new relationships with NPCs and as their own spectrum of responsibilities evolves.
Chiropractic↗
The COMPACCS Study: questions left unanswered. The Committee on Manpower for Pulmonary and Critical Care Societies.
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Critical Care↗
Physiological responses to two wheelchair-racing exercise protocols.
OBJECTIVE: This study investigated the blood lactate accumulation during two wheelchair-racing protocols. During exercise, energy is required, which causes metabolism to increase and blood lactate to accumulate. Proper training can reduce the amount of blood lactate accumulation and increase tolerance to blood lactate accumulation during aerobic exercise. METHODS: Eleven male wheelchair elite track athletes with a spinal cord injury were tested to determine their blood lactate response to speed and resistance workouts. A computer-monitored wheelchair dynamometer was used during all exercise tests. The order of the test (e.g., speed or resistance workout) was randomized. Blood pressure and blood samples were taken immediately before and after completion of each exercise test. RESULTS: The difference between the blood lactate concentrations before and after testing were 8.56 +/- 4.42, and 11.67 +/- 4.69 mM for the resistance and speed tests, respectively. CONCLUSIONS: Our results showed that the blood lactate responses were significantly different for the resistance and speed workouts.
Adult↗
Human inputs: the health care workforce and medical markets.
Arrow wrote his classic article in simpler times, as those who chance upon this article forty years hence will say of today. It was a new era in science and medicine, soon to be fueled by new resources from Medicare and the National Institutes of Health. Fiscal constraint was a stranger, physicians were in short supply, and information asymmetry was pervasive. In the intervening years, Americans have become more comfortable with health care issues. Fatal illness, which was rarely discussed with patients in 1960, is now researched by them on the Internet, and greater attention is paid to patient rights. Nonetheless, concerns about quality have, if anything, increased. Indeed, it is public concern about quality that has invited governmental regulation and induced a defensive posture among medical organizations, which are rushing to establish their own instruments of quality, and it is these same public concerns that have facilitated the ability of managed care to offer itself as the guarantor of quality. However, center stage is now held by another issue: health care costs. As a result, the focus has shifted from resolving information asymmetry by enhancing quality to controlling national health expenditures by changing the size and composition of the health care workforce. Licensure, which was restrictive in 1960, is more relaxed today, thereby reducing the entry barriers for the NPC disciplines, several of which were just beginning when Arrow wrote his article. The entry of NPCs into the realm of physician's services partially counterbalances the constraints that have been placed on physician supply, although the major contributions of NPCs are skewed to the primary care end of the spectrum while the major constraints on physician supply affect specialists. The growing presence of NPCs creates a dynamic market in which practitioners in various disciplines both compete and collaborate. It is, in fact, the perfect market that Arrow reluctantly longed for, in which providers who have different levels of skill offer their services at varying prices. But consumers have little upon which to base their choices. And while many of the services offered by NPCs replace physician services at a lower price, others represent additional services, which add to aggregate spending. Arrow sought to explain how a market replete with uncertainty could function. He saw that licensure, entry rationing, and educational subsidies could work to enhance quality, but they did so at the expense of the market. The market has seen it differently and has usurped these tools for its own purposes, leaving quality to look for other sponsors. Has it done so wisely? We have yet to see how well a multidisciplinary workforce of autonomous providers will function, but both successes and failures abound. What is more apparent is how entry rationing and restrictions on educational subsidies have capped the supply of physicians and limited the production of specialists at a time when there is increasing demand for their services. Arrow identified potent tools for affecting the characteristics of the health care workforce. They now must be redirected to the needs of the future.
Economic Competition↗
Manual wheelchair pushrim biomechanics and axle position.
OBJECTIVE: The biomechanics of wheelchair propulsion have been linked to upper extremity injury. Specifically, prior studies have correlated increased median nerve dysfunction with increasing propulsion frequency and a higher rate of rise of the resultant, or total, pushrim force. Despite this link, there is little research on the effect of wheelchair setup on propulsion biomechanics. The objective of this study was to determine the effect of rear axle position relative to the shoulder on pushrim biomechanics. DESIGN: Case series. SETTING: Biomechanics laboratory. PARTICIPANTS: Forty individuals with paraplegia who use manual wheelchairs for mobility. INTERVENTION: Subjects propelled their own wheelchairs on a dynamometer at two different steady-state speeds and going from a dead stop to maximum speed. Bilateral biomechanical data were obtained using a force- and moment-sensing pushrim and a motion analysis system. MAIN OUTCOME MEASURES: Position of the axle relative to the shoulder at rest both horizontal (XPOS) and vertical (YPOS), and pushrim biomechanical variables including frequency of propulsion, peak and rate of rise of the resultant force, planar moment, and push angle. Partial correlation coefficients between relative axle position and propulsion biomechanics variables were calculated. RESULTS: After controlling for subject characteristics, XPOS was significantly correlated with the frequency of propulsion (p < .01) and the rate of rise of the resultant force (p < .05). In addition, both XPOS and YPOS were significantly correlated with the push angle at multiple speeds (p < .05). CONCLUSION: Specific biomechanical parameters known to correlate with median nerve injuries were found to be related to axle position relative to the shoulder. Providing wheelchair users with adjustable axle position and then fitting the user to the wheelchair can improve propulsion biomechanics and likely reduce the risk of injury.
Adult↗
Allelic modifications of the cg2 and cg1 genes do not alter the chloroquine response of drug-resistant Plasmodium falciparum.
The determinant of chloroquine resistance (CQR) in a Plasmodium falciparum cross was previously mapped by linkage analysis to a 36 kb segment of chromosome 7. Candidate genes within this segment have been previously shown to include two genes, cg2 and cg1, that have complex polymorphisms linked to the CQR phenotype. Using DNA transfection and allelic exchange, we have replaced these polymorphisms in CQR parasites with cg2 and cg1 sequences from chloroquine sensitive parasites. Drug assays of the allelically-modified lines show no change in the degree of CQR, providing evidence against the hypothesis that these polymorphisms are important to the CQR phenotype. Similarly, no change was found in the degree to which verapamil or other chloroquine sensitizers reverse CQR in the transformants. These results and the high though not complete degree of association of CQR with cg2 and cg1 polymorphisms in field isolates suggest involvement of another nearby gene in the P. falciparum CQR mechanism.
Alleles↗
Tumour oxygenation levels correlate with dynamic contrast-enhanced magnetic resonance imaging parameters in carcinoma of the cervix.
BACKGROUND AND PURPOSE: The Eppendorf pO(2) histograph is the 'gold standard' method for measuring tumour oxygenation. The method is not suitable for widespread application because its use is limited to accessible tumours. A non-invasive imaging technique would be an attractive alternative. Therefore, the relationships between tumour oxygenation and dynamic contrast-enhanced magnetic resonance imaging (MRI) parameters were investigated. MATERIALS AND METHODS: The study comprised 30 patients with carcinoma of the cervix. Tumour oxygenation was measured pre-treatment as median pO(2) and the proportion of values less than 5 mmHg (HP5) using a pO(2) histograph. Repeat measurements were obtained for nine patients following 40-45 Gy external beam radiotherapy giving a total of 39 measurements. Dynamic contrast-enhanced MRI using gadolinium was performed prior to obtaining the oxygenation data. Time/signal intensity curves were generated to obtain two standard parameters: maximum enhancement over baseline (SI-I) and the rate of enhancement (SI-I/s). RESULTS: Using the 39 measurements, there was a significant correlation between SI-I and both median pO(2) (r=0.59; P<0.001) and HP5 (r=-0. 49; P=0.002). There was a weak, borderline significant correlation between SI-I/s and both median pO(2) (r=0.29; P=0.071) and HP5 (r=-0. 34; P=0.037). There was a significant relationship between tumour size and SI-I (r=0.54; P<0.001), but not SI-I/s. In 29 tumours, where data were available, there was no relationship between histological assessment of tumour angiogenesis (intra-tumour microvessel density; IMD) and either MRI parameter. CONCLUSIONS: Tumour oxygenation levels measured using a pO(2) histograph correlate with dynamic contrast-enhanced MRI parameters. Therefore, non-invasive dynamic MRI may be a method for measuring hypoxia in human tumours.
Adult↗
Mutations in the P. falciparum digestive vacuole transmembrane protein PfCRT and evidence for their role in chloroquine resistance.
The determinant of verapamil-reversible chloroquine resistance (CQR) in a Plasmodium falciparum genetic cross maps to a 36 kb segment of chromosome 7. This segment harbors a 13-exon gene, pfcrt, having point mutations that associate completely with CQR in parasite lines from Asia, Africa, and South America. These data, transfection results, and selection of a CQR line harboring a novel K761 mutation point to a central role for the PfCRT protein in CQR. This transmembrane protein localizes to the parasite digestive vacuole (DV), the site of CQ action, where increased compartment acidification associates with PfCRT point mutations. Mutations in PfCRT may result in altered chloroquine flux or reduced drug binding to hematin through an effect on DV pH.
Amino Acid Sequence↗
Susceptibility of multiresistant strains of Burkholderia cepacia to honey.
Twenty strains of Burkholderia cepacia, isolated principally from the sputum of cystic fibrosis patients, were tested for their susceptibility to eight antibiotics with a modified Kirby-Bauer Disc diffusion technique. All strains exhibited multiple but not identical patterns of antibiotic resistance. The sensitivity of all strains to honey was assessed with an agar dilution method. All strains exhibited susceptibility to concentrations of honey below 6% (v/v). This suggests that honey may have a potential role in the clinical management of B. cepacia infections.
Burkholderia Infections↗
An evaluation of hospital cleaning regimes and standards.
A four-part study assessing cleanliness in up to 113 environmental surfaces in an operating theatre and a hospital ward is reported. Surfaces were assessed visually, using microbiological methods and ATP bioluminescence. Results from a preliminary random survey indicated variability in cleanliness. These results were then used to select sites for monitoring before and after routine cleaning, over a 14-day period. Using published microbiological and ATP specifications 70 and 76% of these sites were unacceptable after cleaning. Visual assessment was a poor indicator of cleaning efficacy with only 18% considered unacceptable. Sites most likely to fail in the ward were in the toilet and kitchen, areas which are frequently implicated in the spread of infectious intestinal disease. Operating theatre sites had lower ATP results but 61% of sites would be considered unacceptable. There was no significant difference in general microbiological or ATP results overall before and after routine cleaning. Although some important hand contact sites showed no significant difference, overall there was a significant decrease in staphylococcal and enterobacteria counts in the ward but not in the operating theatre after cleaning. The routine cleaning programmes used did not include a biocide and cleaning using a hypochlorite based sanitizer gave much lower values. The results are discussed in relation to infection control, cleaning audits and cleaning schedules: an integrated cleaning monitoring programme using ATP bioluminescence in conjunction with visual and microbiological assessments is recommended.
Adenosine Triphosphate↗
User assessment of manual wheelchair ride comfort and ergonomics.
OBJECTIVE: To examine wheelchair-user perceived ride comfort during propulsion and to compare the ride comfort of ultralight and lightweight manual wheelchairs. An ultralight wheelchair is defined as having a high degree of adjustability, whereas a lightweight wheelchair has minimal adjustability. DESIGN AND PARTICIPANTS: Repeated measures design of a sample of 30 community-dwelling manual wheelchair users evaluating 7 different manual wheelchairs over an activities of daily living course. SETTING: A rehabilitation engineering center. MAIN OUTCOME MEASURES: Subject ratings of perceived ride comfort and basic ergonomics while propelling over the activities of daily living course. Ratings were recorded for each wheelchair on individual tasks and for the course overall. RESULTS: The Invacare Action XT wheelchair was ranked best for both ride comfort and basic ergonomics. The ride-comfort scores (p < .05) and wheelchair ergonomics ratings (p < .05) for the ultralight wheelchair group were significantly different from those for lightweight wheelchair group. CONCLUSION: There are differences in perceived ride comfort and basic ergonomics between the designs of the wheelchairs (lightweight vs ultralight). Subjects perceived that ultralight wheelchairs were more comfortable and had better basic ergonomics than lightweight wheelchairs.
Activities of Daily Living↗
Pretreatment apoptosis in carcinoma of the cervix correlates with changes in tumour oxygenation during radiotherapy.
A relationship between hypoxia and apoptosis has been identified in vitro and in experimental tumours. The aim of this study was to investigate the relationship between apoptosis, hypoxia and the change in oxygenation during radiotherapy in human squamous cell carcinoma of the cervix. Forty-two patients with locally advanced disease underwent pretreatment evaluation of tumour oxygenation using an Eppendorf computerized microneedle electrode. Twenty-two of these patients also had a second evaluation of tumour oxygenation after receiving 40-45 Gy external beam radiotherapy. Paraffin-embedded histological sections were obtained from random pretreatment biopsies for all 42 patients. Apoptotic index (AI) was quantified by morphology on TUNEL stained sections. No correlation was found between pretreatment measures of AI and either the median pO2 (r = 0.12, P = 0.44) or percentage of values < 5 mmHg (r = -0.02, P = 0.89). A significant positive correlation was found between AI and the change in tumour oxygenation (ratio of pre:post-treatment % values < 5 mmHg) following radiotherapy (r = 0.61, P = 0.002). The lack of correlation between apoptosis and hypoxia may occur because the Eppendorf measures both acute and chronic hypoxia, and the relative ability of acute hypoxia to induce apoptosis is unknown. These results indicate that cell death via apoptosis may be a mechanism of tumour reoxygenation during radiotherapy.
Adult↗