The extraction of lipid from human blood and other biological materials in the determination of dioxin-like and organochlorine compounds has been studies using different amounts of extracting solvent. When large volumes of ethanol-hexane are used to extract small blood samples, the total lipid extracted is incomplete as the polar phospholipids do not partition into the organic phase. This failure to extract all the blood lipid results in an inaccurately high concentration expressed on a lipid basis and, by corollary, a high biased body burden. This solvent dependence of lipid extraction does not appear to be a problem for most other biological and food samples since over 90% of the lipid is in the form of readily extractable neutral glycerides.

Adipose Tissue↗

PubMedDate not supplied

Comparison of EPA's QMS to SEI's CMMI.

EPA and other government organizations make decisions based on environmental measurements. How good are the data? How well are the data generators performing? What measurements apply to them? How can the data life cycle processes be improved so data generators can continually provide the best data? EPA's Quality Management System requirements go beyond evaluation of environmental data quality itself to examine systems associated with production, collection, processing (validation/verification), transfer, reduction, storage, and retrieval of data throughout a life cycle. This QMS specifies minimum quality requirements for particular environmental programs. But how can you measure and compare programs that go well beyond the minimum, towards optimal quality? This paper compares EPA's requirements for Quality Management Systems (R2) and Project Plans (R5) to the Software Engineering Institute Capability Maturity Model (CMMISM). The CMMISM model provides for growth (staged or continuous) and a comprehensive assessment that is not yet provided in EPA's R2 or R5. Properly implemented, the CMMISM model serves as a quality framework for integrating and aligning organizational processes and implementing a program of continual process improvements. It identifies process areas ("things to do"), and provides measures of performance ("how well things are done") against specific goals and practices. CMMISM uses a Systems Engineering Management approach, built on process models, that helps identify "how good" the system is. Goodness is defined as stages in a complete model for optimal operation. CMMISM provides two methods for evaluating the goodness of the project. The Staged model in CMMISM provides a Maturity Level that is a well-defined evolutionary plateau describing the manner in which a specified set of processes are performed. As the organization advances in maturity, these levels become more defined and processes are tailored for specific project needs. The other method is called the Continuous Model in CMMISM, and it allows you to achieve Capability Levels. These are used to describe how well each project is doing in relationship to the different process areas. There are six Capability Levels from 0-5 that apply to individual process areas. Organizations using the Capability Level approach can select individual process areas that are important to specific projects and work to improve the processes. Improving capability in individual process areas raises the organization's overall quality of products delivered. The Continuous Model, unlike the Staged Model, lets you pick higher maturity level process areas before completing all of the ones below. Environmental measurement programs need to focus on the quality of the systems where data are collected, processed, transferred, and so forth. DynCorp built on the quality foundation from our experience with R2 to successfully implement CMMISM practices in the development of Forms II Lite and other applications. DynCorp is now migrating to the CMMISM model that has evolved from the existing CMM model. The CMMISM model focuses on the full cycle of Requirements Management from identification, development, collection, refinement, analysis, and validation throughout a project life cycle. It also has a more refined focus on the identification, development, collection, analysis, and evaluation of meaningful measurements, so the results can be used to improve a process or product.

Academies and Institutes↗

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Evaluation of topical therapeutic ultrasound to improve response to physical therapy and lessen scar contracture after burn injury.

This study compared results of patients who received standard burn physical therapy and topical ultrasound with patients who received standard care alone to investigate the effect of topical therapeutic ultrasound on range of motion and pain in patients with burns. Fourteen burned extremities were studied. Eight joints were randomized to treatment with ultrasound followed by 10 minutes of passive stretching. Six joints received placebo ultrasound treatments and stretching. All treatments were performed every other day throughout a 2-week study period. Joint range of motion was measured before and after each treatment, and patients estimated the pain of the procedure. Patients and therapists were blinded to the treatment group. Analysis of the data revealed no differences in range of motion or perceived pain between the two groups. The effect of ultrasound on range of motion and pain was not predictable. We conclude that patients are not likely to improve from ultrasound treatment at our protocol parameters.

Adult↗

PubMedDate not supplied

Uses of Coban self-adherent wrap in management of postburn hand grafts: case reports.

Coban wrap is a durable, elastic, self-adherent gauze that applies snugly without loosening. Coban does not stick to underlying tissue, making it excellent for early postoperative management of split- and full-thickness hand grafts. The wrap protects new grafts and decreases postoperative edema, permitting earlier mobility and facilitating accurate measurements for fitting of pressure garments. Wounds are judged suitable for Coban when the grafts are largely adherent and vascularized. Coban can be wrapped (1) directly over the graft, (2) over an ointment/adaptic dressing, or (3) over gauze padding for extra protection, or use as a "soft splint." Because of its inherent elasticity, Coban can be used to passively encourage desirable joint positions. The wrap is changed daily, and family members readily learn its use. Coban appears to encourage early, protected, active range of motion and early use of custom-fit pressure garments.

Adult↗

PubMedDate not supplied

A quantitative technique for characterizing tasks in psychophysiology studies.

A model was designed to specify the components of blood pressure (BP) in a reactivity study. The model considered six components for BP in response to tasks: the average resting BP across all subjects, a given subject's deviation from that average, the average task effect for a specific task, a given subject's deviation from the average task effect, the average effect of repeated assessments of BP within a given task, and an error term. The model and data from 71 adult men were used to estimate the components represented by averages. The variances and covariances of the components were represented by deviations from this average. Utilizing the likelihood ratio statistic with the bootstrap null distribution, the model gives a reasonable representation of the data. Alternative models were also tested; however, they fell short of representing the data well. The fitting and testing of components in models like ours may offer some guidance in the design of future reactivity studies.

Adult↗

PubMedDate not supplied

Effects of chronic stress on beta-adrenergic receptors in the homeless.

This study examined the role of chronic life stress (homelessness), coping style, and hypertension on beta-adrenergic receptors in a sample of homeless men. Sixteen healthy normotensive subjects and nine untreated hypertensive subjects were studied. Life stress was measured with the Brown and Harris categorization; coping style was measured with the Ways of Coping Scale. Lymphocyte beta-adrenergic receptors were characterized in terms of receptor density (Bmax). Individuals with high life stress had lower Bmax (p < .005). In multiple regression analyses, 50% of the variance in Bmax was accounted for by life stress and coping style (p = .01). Receptor measures may be useful for characterizing the physiological response to continuing life adversity.

Adaptation, Psychological↗

PubMedDate not supplied

Bipolar leads for use with permanently implantable cardiac pacing systems: a review of limitations of traditional and coaxial configurations and the development and testing of new conductor, insulation, and electrode designs.

The unacceptable rate of mechanical failures, threshold problems, and recalls experienced with many coaxial bipolar cardiac pacing lead designs are reviewed in detail. To address these problems, redundant insulation coradial atrial and ventricular tined leads (AL and VL, respectively) with iridium oxide electrodes were developed and subjected to extensive accelerated testing. There were no mechanical failures. The new lead body design proved to be much more durable than widely used trifilar MP35N configurations. The data reviewed and early and current test results are strongly supportive of tightly coupled insulation being a major factor in improving lead durability as long as the insulating material is not stressed. In addition to improving flex life, insulation adherence to the conductor may reduce the potential for ionic degradation. Pacing and sensing thresholds in animal studies of the new leads were within the reported range for leads with steroid eluting electrodes. A multicenter Canadian clinical trial was initiated with the first implant in early January 1994. By November 1995, 110 VL and 82 AL had been placed in 124 patients and followed for a mean of 11 +/- 6 months; maximum 21, total 1355. There were 60 males and 64 females with a mean age of 64 +/- 16 years, range 15-88. Primary indications for pacing were AV block in 61 patients, sick sinus syndrome in 53, vasovagal syncope in 4, and congestive heart failure in 7. Many patients had associated or primary tachyarrhythmias, including 111 with supraventricular and 12 with ventricular. Forty-two percent of patients (52/124) had prior cardiac procedures, including 18 open heart surgeries and 20 AV nodal ablations. At implant, 8 lead characteristics were rated good or excellent in 90% (746/829) of evaluations. X-ray visibility was of concern in 10% of patients (12/124). Three perioperative complications occurred, including displacement of one AL (1.2%) and one VL (0.9%). There were no subsequent mechanical (connector, conductor, or insulation) or functional (exit block, micro or macro displacement, or over- or undersensing) problems. Implant pacing thresholds (PT) at 0.45 ms were AL, 0.6 +/- 0.2 (74) and VL 0.4 +/- 0.2 V; impedance (Z) at 3.5 V output AL 373 +/- 77 (82) and VL 497 +/- 117 omega. Sensing thresholds (ST) were AL 3.1 +/- 1.6 (74) and VL 10.3 +/- 4.9 mV. Ventricular lead data were obtained for all patients (N = 110). Atrial lead data are incomplete, because some patients were in atrial fibrillation during implantation. After 12 months, AL PT at 1.5 V output was 0.18 +/- 0.10 ms (21) and at 2.5 V was 0.10 +/- 0.053 (22). Associated AL ST was 3.3 +/- 0.9 mV (21) AL Z 500 +/- 65 omega (25). After 18 months VL PT at 1.5 V was 0.15 +/- 0.10 ms (9) and at 2.5 V output was 0.09 +/- 0.04 ms (9). Associated VL ST was > 7.5 +/- 2.4 mV (9) and VL Z 497 +/- 105 omega (9). Follow-up time discrepancy is due to the VL being available 6 months earlier than the AL. There were no 30-day deaths and only one late death at 10 months in a patient with chronic atrial fibrillation. Death was unrelated to pacer or lead function. At 1 year, 68% AL (15/22) and 62% (24/39) captured at 0.5 V and < or = 1 ms pulse width output. Innovative adherent insulation coradial bipolar lead conductors of the design studied combined with coated iridium oxide electrodes provide for a negligible incidence of mechanical or functional failure with clinical follow-up now approaching 3 years. Excellent acute and chronic sensing and pacing thresholds have been documented. Late thresholds have continued to improve gradually. Long-term clinical pacing at < or = 1.5 V output with a large safety margin is feasible in essentially all patients. This coradial design produces very flexible < 5 French bipolar redundantly insulated lead bodies allowing both AL and VL to simultaneously pass through a single 10 French introducer sheath. (ABSTRACT TRUNCATED)

Cardiac Surgical Procedures↗

PubMedDate not supplied