Biomedical subjects
Publications and source records attributed to David Williams.
A new ceramic material was introduced into clinical practice five years ago with the expectation that it would improve performance and give better fracture toughness and wear resistance. In reality, the reverse happened and far more failures have occurred. This article asks whether there are any lessons to be learnt.
In the United States,the Food and Drug Administration (FDA) and the National Institutes of Health have noted a significant decrease in the number of innovative products reaching patients, in spite of a rapidly expanding basis of fundamental scientific knowledge. A recent FDA report proposes some solutions to this problem.
An editorial just published in Naturel draws attention to a profound issue concerned with the risks associated with the introduction of new technologies into medical practice. The risks are derived from the way in which genes are delivered, and central to the solutions to these problems may be some innovative materials and device designs.
This paper presents findings from formative research exploring Black Seventh-day Adventist church members' attitudes about Black non-participation in past studies, and suggestions for recruiting 45,000 Blacks to an upcoming longitudinal cohort study. Data were collected in California and Pennsylvania, using 15 key informant interviews and 6 focus groups. Key findings supported and elucidated existing literature on the barriers to minority recruitment, and included: a general mistrust of the medical/scientific community; a perception that providing informed consent relinquishes, rather than protects, an individual's rights; a perception of being "studied" rather than "studying," due to the paucity of Black investigators; and a perceived lack of cultural sensitivity in the recruitment of Blacks, and in the conduct of the research itself. Building trust throughout the process, from clearly demonstrating the benefits of participation, at the individual and community level, to including Blacks in the study design from conceptualization to data analysis and presentation, emerged as a critical component in garnering Black participation in future studies.
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BACKGROUND: Intravascular contrast agents presently used in modern digital catheter laboratories during cardiac catheterization are superior to older agents as regards patient tolerance. There are, however, significant differences between these agents. PURPOSE: The aim of this study was to determine the incidence of early (< 24 hours) and late (> 24 hours to 7 days) reactions to 2 contrast agents currently used during cardiac catheterization: iopamidol 340 (Niopam) and iobitridol 350 (Xenetix). METHODS: This was a prospective, randomized, double-blinded trial. Two thousand and nineteen patients undergoing cardiac catheterization received one of the following contrast agents: iopamidol 340 (Niopam) and iobitridol 350 (Xenetix). Reactions that were possibly related to the contrast agents were recorded during hospital admission (early reaction) and after discharge (late reaction) by means of a questionnaire. RESULTS: The baseline characteristics were matched in both the groups. There was no significant difference in the incidence of heat sensation experienced between the 2 groups, (p = 0.1). Early non-heat reactions occurred in 3.2% of patients receiving iopamidol 340 (Niopam) and 3.6% of those receiving iobitridol 350 (Xenetix), (p = 0.65). Electrocardiographic changes were recorded in 0.7% of patients who received iopamidol 340 (Niopam), and 2.6% of those who received iobitridol 350 (Xenetix), (p = < 0.01). Seven patients (0.8%) receiving iobitridol 350 suffered ventricular fibrillation requiring DC cardioversion compared with none in the iopamidol 340 group (p = < 0.01). Late reactions (post discharge symptoms) occurred in 13.9% of those receiving iopamidol 340 (Niopam) and 18.5% of those receiving iobitridol 350 (Xenetix) (p = 0.02). CONCLUSIONS: Iobitridol 350 (Xenetix) was associated with more ECG changes and, importantly, ventricular fibrillation, than iopamidol (Niopam). There were no features to suggest other benefits from iobitridol 350. These results suggest that iopamidol 340 is a preferable contrast agent in cardiac catheterization.
A recently published report has reassessed the meanings of nanoscience and nanotechnology and considered the opportunities and hazards that arise within this area. Some of the factors relevant to medical nanotechnology are considered here.
The spinal column, and in particular the intervertebral discs that separate the vertebral bodies, provide a focal point for degenerative change and chronic pain. This article addresses the changing role of medical technology used in the therapeutic alternatives for this widespread condition.
During the past few years, new concepts of materials synthesis have been developed in which macromolecular structures form by-processes of self-assembly. Microstructures and nanostructures, which often mimic those found in nature, are formed without complex manufacturing methods. This article assesses the implications of this development for medical devices.
PURPOSE: To assess which postoperative patients benefit most from MR arthrography of the knee. MATERIALS AND METHODS: One hundred consecutive MR arthrograms obtained in patients who had previous knee surgery underwent retrospective review in consensus by three radiologists after prospective reading by one of the three radiologists. Criterion on MR arthrograms for a retear was abnormal tracking of an intraarticular dilute gadolinium-based contrast material and saline mixture into the substance of a meniscus. Patients were separated into three groups: those with more than 25% meniscal resection, those with less than 25% meniscal resection, and those with meniscal repair. All 100 patients had preoperative MR images to review directly in conjunction with the postoperative MR images. Fifty-seven of these 100 patients underwent second-look arthroscopy. RESULTS: Nine patients had MR findings consistent with avascular necrosis. Nineteen patients had marked degenerative arthrosis in the area of previous surgery. Seven patients had chondral defects or injuries. Twenty-nine patients had clear MR evidence of a meniscal retear without any contrast material injected into the joint. In 32 of the 100 patients, intraarticular contrast material was useful in demonstrating a retear. Of these 32 patients, 22 had MR arthrographic evidence of a retear, while 10 had no clear MR arthrographic finding to explain postoperative pain. Four additional patients had no clear MR imaging or MR arthrographic abnormality. All patients with meniscal repair (n = 16) needed MR arthrography to diagnose a residual or recurrent meniscal tear. No patient with less than 25% meniscal resection (n = 23) needed MR arthrography to demonstrate a residual or recurrent meniscal tear. Sixteen of 61 patients with more than 25% meniscal resection needed MR arthrography to demonstrate a residual or recurrent meniscal tear. CONCLUSION: All patients with meniscal repair required MR arthrography. All patients with meniscal resection of more than 25%, who did not have severe degenerative arthrosis, chondral injuries, or avascular necrosis required MR arthrography. Patients with less than 25% meniscal resection did not need MR arthrography.
The speed with which one reacts to an imperative signal depends on the extent to which preceding cues predict that command. When reliable warning cues are available, the processing of the imperative stimulus can be favoured and responses partially pre-prepared, leading to shorter reaction times. Here we seek evidence for involvement of the human basal ganglia in the exploitation of behaviourally relevant predictive cues. To this end, local field potentials (LFPs) were recorded in the region of the subthalamic nuclei of parkinsonian patients during the performance of a pre-cued reaction task in which the cue either predicted or failed to predict the demands of the imperative signal. We demonstrate that LFP activity in the beta frequency band ( approximately 20 Hz) is modulated by the behavioural relevance of the external cue. The findings suggest that, first, the subthalamic nucleus is involved in mediating or facilitating the response advantage derived from predictive cues in humans and, secondly, variations in synchronous neuronal activity in the beta band may contribute to this function in the subthalamic nucleus.
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BACKGROUND AND PURPOSE: Xerostomia is a significant morbidity of radiation treatment in the management of head and neck cancers. We hypothesized that the surgical transfer of one submandibular salivary gland to the submental space, where it can be shielded from radiation treatment (XRT), would prevent xerostomia. MATERIALS AND METHODS: We conducted a prospective Phase II clinical trial and the patients were followed clinically with salivary flow studies and the University of Washington Quality of Life questionnaire. RESULTS: We report the results on 76 evaluable patients. The salivary gland transfer was done in 60 patients. Nine patients (of 60) did not have postoperative XRT and in eight patients (of 60) the transferred gland was not shielded from XRT due to proximity of disease. The median follow up is 14 months. Of the 43 patients with the salivary gland transfer and post-operative XRT with protection of the transferred gland, 81% have none or minimal xerostomia, and 19% developed moderate to severe xerostomia. Three patients (6.9%) developed local recurrence, five patients (11.6%) developed distant metastases and five patients (11.6%) have died. There were no complications attributed to the surgical procedure. CONCLUSION: Surgical transfer of a submandibular salivary gland to the submental space preserves its function and prevents the development of radiation induced xerostomia.
AIMS: To determine if a gender or age bias exists in the prescription of important secondary preventive therapies for ischaemic heart disease in primary care. METHODS: We identified 15 590 patients with ischaemic heart disease on the basis that they received a prescription for nitrate therapy over a 1-year period (September 1999 to August 2000) from the Eastern Region of the General Medical Services scheme in Ireland (population of 334 031), which provides free health service to those eligible patients in primary care. Odds ratios (OR) for the prescription of aspirin, beta-blockers, statins, calcium channel antagonists and ACE inhibitors in women and in those aged> 65 years were determined. RESULTS: Female patients were less likely to receive a prescription for a beta-blocker [OR = 0.84, 95% confidence interval (CI) = 0.79, 0.89, P < 0.001], aspirin (OR = 0.72, 95% CI = 0.67, 0.78, P < 0.001), and ACE inhibitors (OR = 0.83, 95% CI = 0.78, 0.89, P < 0.001) compared with their male counterparts. However, women were more likely to receive anxiolytic benzodiazepines (OR = 1.71, 95% CI = 1.59, 1.85, P < 0.001) compared with their male counterparts. Elderly patients (aged> 65 years) were less likely to receive aspirin (OR = 0.92, 95% CI = 0.85, 0.99, P < 0.001), beta-blocker (OR = 0.66, 95% CI = 0.62, 0.71, P < 0.001) and a statin (OR = 0.5, 95% CI = 0.46, 0.53, P < 0.001). CONCLUSIONS: An age and gender bias exists in the prescription of important secondary preventive therapies in primary care that may lead to increased mortality from ischaemic heart disease in these groups.
BACKGROUND: A significant body of research suggests that religious involvement is related to better mental and physical health. Religion or spirituality was identified as an important health protective factor by women participating in the East Side Village Health Worker Partnership (ESVHWP), a community-based participatory research initiative on Detroit's east side. However, relatively little research to date has examined the mechanisms through which religion may exert a positive effect on health. OBJECTIVE: The research presented here examines the direct effects of different forms of religious involvement on health, and the mediating effects of social support received in the church as a potential mechanism that may account for observed relationships between church attendance and health. DESIGN: This study involved a random sample household survey of 679 African-American women living on the east side of Detroit, conducted as part of the ESVHWP. MAIN RESULTS: Results of multivariate analyses show that respondents who pray less often report a greater number of depressive symptoms, and that faith, as an important source of strength in one's daily life, is positively associated with chronic conditions such as asthma or arthritis. Tests of the mediating effect of social support in the church indicated that social support received from church members mediates the positive relationship between church attendance and specific indicators of health. CONCLUSIONS: These findings are consistent with the hypothesis that one of the major ways religious involvement benefits health is through expanding an individual's social connections. The implications of these findings for research and practice are discussed.
The purpose of the present study was to compare the use of lorazepam plus nitroglycerine (NTG) versus NTG alone in the reduction of cocaine induced chest pain in the emergency department. The secondary objective of the study was to help determine the safety of lorazepam in the treatment of cocaine- associated chest pain. The study was a prospective, randomized, single-blinded, controlled trial conducted at an university-affiliated urban emergency department (ED). All patients who presented with cocaine-associated chest pain were enrolled. Exclusion criteria included age greater than 45 years, documented coronary artery disease, chest pain of more than 72 hours duration, or pretreatment with nitroglycerin. Patients were given either sublingual nitroglycerine (SL NTG) (Group 1) or SL NTG plus 1 mg of lorazepam intravenously (Group 2) every 5 minutes for a total of 2 doses. Chest pain was recorded on an ordinal scale of 0 to 10 at baseline, and then at 5 minutes after each dose. Adverse reactions to medication were also recorded. Twenty-seven patients met the inclusion criteria and were enrolled in the study. The average age of these subjects was 34.1 years, and 67% were men. The NTG-only group consisted of 15 patients and the NTG-plus-lorazepam group consisted of 12 patients. Baseline mean chest-pain scores were 6.87 in Group 1 and 6.54 in Group 2, with no differences between groups. Five minutes after initial treatment, mean scores for the two groups were 5.2 and 3.9, respectively, with a difference in means of 1.24 (95% confidence interval [CI] -0.8-3.8). Five minutes after the second treatment, the mean scores were 4.6 and 1.5, respectively, with a difference in means of 3.1 (95% CI 1.2-5). Kruskal-Wallis testing showed a significant difference in pain relief between the two study groups (P =.003), with greater pain relief noted at 5 and 10 minutes in the NTG-plus-lorazepam group (P =.02 and P =.005, respectively). All patients in the study were admitted to the hospital, but no patient in either group had an acute myocardial infarction or cardiac complications in the ED. No adverse side effects were noted for either group. The early use of lorazepam with NTG was more efficacious than NTG alone, and appears to be safe in relieving cocaine-associated chest pain.
BACKGROUND: Several studies have demonstrated that 25-40% of Accident & Emergency department attendances are for conditions that could be managed by the patient's general practitioner. The number of these who could be appropriately managed by a community pharmacist, has not previously been established. OBJECTIVE: To establish the frequency with which patients attend an inner city A&E department with problems that could be managed by a community pharmacist. METHODS: A cross-sectional, retrospective review of A&E records for adult patients (>16 years) was conducted during the first two weeks of March 1999. Application of recognised criteria identified patients whose conditions were suitable for treatment by a pharmacist. Associated patient characteristics were investigated. RESULTS: During the study period 2636 adult patients attended the A&E department. Pharmacist management was considered appropriate in 8% of adult attendances (95% CI 6.8-8.9). The most commonly presented symptoms considered appropriate for pharmacist treatment included those of upper respiratory, gastrointestinal and pain conditions and reflect those previously identified in the literature. CONCLUSIONS: A pharmacist could manage an estimated 8% of adult attendances at this A&E department. Efforts should be made to increase the awareness of the general public of the role of a community pharmacist to reduce demand on A&E and GP services.