Biomedical subjects
Publications and source records attributed to D Williams.
All medical devices have to be sterilized, but the process of killing bacteria and other organisms can also have some deleterious effects on the devices themselves. This article discusses the mechanisms by which gamma irradiation can cause polymer damage and the potential consequences of this.
Balloons and catheters together form an increasingly important combination in diagnostic and therapeutic minimally invasive procedures. This article discusses how these simple devices have risen in stature over the last decade.
Collagen is a protein that is widely distributed in humans and plays an important role in many aspects of tissue performance. This versatility is central to the uses of collagen in biomedical devices. The structure and properties of collagen and the basis for their biomedical uses are described in this article.
Poly(vinyl chloride) (PVC) is a widely used commodity plastic that has many applications in medical devices. Recent concerns over the oestrogenic activity of some of the phthalate plasticizers used in PVC, and the hazards associated with dioxin that may be produced during the incineration of PVC waste have initiated an assessment of the future role of this material. This article addresses some of the underlying toxicological and risk assessment issues.
This study investigated various designs of stress breakers incorporated into the dental implant using 3-D finite element analysis. These designs employed hydroxyapatite-reinforced polyethylene (HRP), a material capable of inducing osseointegration. The most successful design was that of a dental implant with a peripheral HRP component that was in direct contact with the bone surrounding the neck of the implant. This design lowered the compressive stress values in bone around the neck of the implant. Attempts were also made to optimize this design.
Are medical products killer devices or life-improving instruments? This issue is being fought out in the general media today. The first article in a new series of the Material Matters column discusses this unwelcome phenomenon and examines the arguments.
The aim of our study was to examine whether there is an association between blood pressure reactivity to the cold pressor test in African Americans who engaged in different levels of physical activity. We examined the systolic pressure, diastolic pressure, mean arterial blood pressure, heart rate, cardiac index, total peripheral resistance, and forearm blood flow during a two-minute cold pressor test in 15 aerobic, physically active and 15 physically inactive, normotensive young adult African-American males. Peak oxygen consumption varied as a function of physical activity, and was significantly higher in the physically active than in the physically inactive subjects (54.5 +/- 1.5 vs 36.8 +/- 0.7 ml kg(-1) min(-1)) (P<.05). During the cold pressor test, consisting of immersing the foot in ice water, the change in cardiovascular responses were similar between the physically active and the physically inactive groups. These results suggest that regular physical activity may not contribute to an attenuated blood pressure response to behavioral stress of the cold pressor test in normotensive young adult African-American males.
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This CEU program will assist the nurse in planning quality care for the patient who experiences urinary incontinence. A review of the urinary system is presented so that an adequate understanding of the types and causes of urinary incontinence may be achieved. Assessment data to be obtained by the nurse are included and appropriate nursing interventions are discussed.
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Intravenous sufentanil, an analog of fentanyl, was compared to diazepam for conscious sedation in ambulatory dental outpatients. Ten patients undergoing the surgical removal of impacted third molars served as subjects in a double-blind, within-subject, single crossover study. Sedation was achieved with a combination of 30% nitrous oxide/70% oxygen by nasal mask and either diazepam (0.05-0.15 mg/kg) or sufentanic (0.05-0.15 μg/kg) titrated to a clinical endpoint of altered speech and relaxation. Intraoperative physiologic monitoring, patients' and the oral surgeon's subjective estimates of efficacy and psychomotor recovery were used to compare the two treatments. Both patients (eight of 10) and surgeons (six of 10) preferred sufentanil sedation. No significant differences were noted between treatments for psychomotor recovery. These preliminary data in a small sample suggest that sufentanil produces adequate conscious sedation in dental outpatients and should be evaluated further with larger patient samples.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.