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Biomedical subjects

C Williams

Publications and source records attributed to C Williams.

At least 703 records · Page 39Linked to original sources
PubMedDate not supplied

Repeatability of treadmill exercise ejection fraction and wall motion using technetium 99m-labeled sestamibi first-pass radionuclide ventriculography.

BACKGROUND: Peak treadmill exercise radionuclide ventriculography (RVG) with technetium 99m has recently been validated for determination of left ventricular ejection fraction (LVEF). However, the repeatability of this technique for determination of both LVEF and regional wall motion has not been reported. METHODS AND RESULTS: Each of 27 clinically stable patients underwent two treadmill exercise RVG studies within 40 +/- 51 days. The level of exercise achieved in the two tests was similar (double product: 26,357 +/- 3877 vs 26,621 +/- 4287), and there was no change in clinical or treatment status between the studies. Acquisition and processing were accomplished with a mobile multicrystal camera and a new version of a commercial software (Scinticor SIM 400 V. 4.1 BETA, Milwaukee, Wis.) that uses two left ventricular regions of interest. The two tests were compared to assess agreement (repeatability) on both an automatically calculated LVEF and wall motion in five left ventricular segments (basal anterior, distal anterior, apical, distal inferior, and basal inferior), with a 3-point semiquantitative visual score. Intraobserver and interobserver agreements (reproducibility) also were assessed on quantitative exercise LVEF derived from the same RVG test from a separate group of 20 patients with a broad range of exercise LVEF. The first and second treadmill exercise LVEFs were highly correlated (r = 0.92, SEE = 3.96, y = 0.97x + 0.58; and r = 0.99, SEE = 1.32, y = 0.99x + 0.25, respectively). Results of segmental visual score agreement between the first and the second treadmill first-pass studies were as follows: overall, 86% (116/135, kappa = 0.74); basal anterior, 85% (23/27, kappa = 0.72); distal anterior, 85% (23/27, kappa = 0.84); apical, 93% (25/27, kappa = 0.85); distal inferior, 93% (25/27, kappa = 0.80); and basal inferior, 67% (18/27, kappa = 0.64). CONCLUSION: Treadmill exercise first-pass RVG is a highly repeatable and reproducible test for quantitative LVEF and visual regional wall motion analysis. Our results imply the procedure may be useful for serial follow-up of patients with coronary artery disease and for the evaluation of the efficacy of medical or interventional treatment.

Adult↗
PubMedDate not supplied

Binary quantitative structure-activity relationship (QSAR) analysis of estrogen receptor ligands.

The use of high throughput screening (HTS) to identify lead compounds has greatly challenged conventional quantitative structure-activity relationship (QSAR) techniques that typically correlate structural variations in similar compounds with continuous changes in biological activity. A new QSAR-like methodology that can correlate less quantitative assay data (i.e., "active" versus "inactive"), as initially generated by HTS, has been introduced. In the present study, we have, for the first time, applied this approach to a drug discovery problem; that is, the study of the estrogen receptor ligands. The binding affinities of 463 estrogen analogues were transformed into a binary data format, and a predictive binary QSAR model was derived using 410 estrogen analogues as a training set. The model was applied to predict the activity of 53 estrogen analogues not included in the training set. An overall accuracy of 94% was obtained.

Cluster Analysis↗
PubMedDate not supplied

Human pro alpha 1(I) collagen gene structure reveals evolutionary conservation of a pattern of introns and exons.

The collagens represent an interesting example of a structurally related but genetically distinct family of proteins. Type I, the most abundant of the vertebrate collagens, comprises two pro alpha 1(I) chains and one pro alpha 2(I) chain, each containing terminal propeptides and a central domain of 338 (Gly, X, Y) repeats. The structure of the chicken pro alpha 2(I) gene shows an intriguing relationship between exon organization and the arrangement of (Gly, X, Y) repeats (see ref. 2 for review). This has led to the suggestion that the collagens evolved from a common ancestral unit of 54 base pairs (bp). Here we present the structure of the entire human pro alpha 1(I) gene and compare this with the chicken pro alpha 2(I). The exon arrangement of the two genes is remarkably similar, although the human pro alpha 1(I) is more compact because of the shorter length of its introns. The data strongly support the notion that the type I genes have evolved from an ancestral multi-exon unit, and that once the gene was translated, a strong evolutionary pressure caused it to maintain this elaborate structure.

Amino Acid Sequence↗
PubMedDate not supplied

Sustained reduction of exercise perfusion defect extent and severity with isosorbide mononitrate (Imdur) as demonstrated by means of technetium 99m sestamibi.

BACKGROUND: The impact of long-acting nitrates on the extent and severity of stress-induced myocardial ischemia is not well described, especially after long-term treatment. METHODS: Forty patients with chronic stable angina and reversible ischemia on an exercise stress myocardial perfusion single photon emission computed tomography (ex-SPECT) were prospectively studied in a 6-week period. At baseline, rest thallium-201/exercise stress technetium 99m sestamibi SPECT was performed, followed by treatment with extended-release isosorbide 5-mononitrate (5-ISMN, Imdur). Follow-up ex-SPECT was performed 5 days and 6 weeks after the initiation of therapy with extended-release 5-ISMN. The exercise treadmill testing (ETT) protocol and exercise duration of the follow-up studies were the same as that of the baseline ETT. Defect extent and severity were analyzed both by means of an automated quantitative method, with CEqual software, and visually, with a 20-segment scoring system (which was also used to derive a summed stress score [SSS]). RESULTS: In the 6-week study period, significant reductions occurred in both the extent and the severity of exercise-induced ischemia by means of quantitative SPECT (13.8% [P<.0003] and 12.7% [P<.0003], respectively). There was no significant change in these variables between stages 2 (day 5) and 3 (6 weeks), indicating no development of tolerance to the nitrate effect. Similar reductions were noted by means of the visual analysis (SSS reduction of 13.0% [P<.002]) in the entire study period. CONCLUSIONS: Patients with chronic-stable-angina treated with a long-acting nitrate demonstrate improvement in myocardial perfusion defect extent and severity in an extended period by means of both visual and quantitative analysis of sequential exercise testing to the same rate-pressure product end point.

Aged↗
PubMedDate not supplied

Adjunctive hyperbaric oxygen therapy reduces length of hospitalization in thermal burns.

The use of adjunctive hyperbaric oxygen therapy as part of a comprehensive program of burn care at our institution has resulted in a statistically significant reduction in length of hospital stay (p = less than 0.012) with no increase in cost of hospital care in patients suffering burns over 18% to 39% of total body surface area.

Adolescent↗
PubMedDate not supplied

Adjunctive hyperbaric oxygen in the treatment of thermal burns. An economic analysis.

Current reimbursement for burn care underscores the importance of cost containment in the treatment of burn injuries. We evaluate the economic impact of adjunctive hyperbaric oxygen in burns of 19% to 50% total body surface area in patients admitted to our burn center from January 1982 to July 1987. Length of hospitalization, number of surgical procedures, and total cost of care, exclusive of surgical fees, were examined. Eleven patients did not receive adjunctive hyperbaric oxygen therapy, whereas 10 did. The hyperbaric oxygen-treated group had an average decrease in length of stay of 14.8 days, a reduction of surgical procedures of 39%, and an average saving per case of $31,600.

Adolescent↗
PubMedDate not supplied

Linking substance-abusing pregnant women to drug treatment services: a pilot program.

OBJECTIVE: To conduct a pilot study to assist pregnant substance abusers to enter drug treatment. DESIGN: A nonexperimental design provided eligible women with outreach/home visits from a team led by a public health nurse. SETTING: All services for the women were provided in homes in the northeastern United States. PARTICIPANTS: Ten pregnant substance-abusing women who were not in drug treatment upon entry into prenatal care enrolled in the project. INTERVENTIONS: Home visits by a public health nurse were provided to the women to jointly develop a plan of care targeted to each woman's needs. A substance abuse counselor was available as a consultant and for home visits. An interdisciplinary team met monthly to coordinate services, discuss therapeutic approaches and treatment strategies, and address needed changes in the health services system. MAIN OUTCOME MEASURES: Rates of entry into substance abuse treatment, retention of custody of the index child, and scores on the Addiction Severity Index (ASI). RESULTS: Although the expected rate of entry into treatment was 10%, 90% of the women (n = 9) entered treatment. All had full-term newborns. Eighty percent (n = 8) retained custody of the index child. Upon the participants' enrollment, ASI scores indicated a moderate to extreme problem with alcohol and drug use for all women, and moderate to extreme psychiatric problems for 89% of the women. Subsequent ASI scores demonstrated marked improvement in all three subscales. CONCLUSION: This project provides strategies that nurses can use to assist substance-abusing pregnant women to enter drug treatment.

Adolescent↗
PubMedDate not supplied

Broken past, fragile future: personal stories of high-risk adolescent mothers.

PURPOSE: To uncover what adolescent mothers view as their childhood struggles, their transition to the role of motherhood following a childhood of abuse/neglect, and their important relationships after they became parents. DESIGN: Qualitative, phenomenological. SETTING: Community-based parenting program for first-time mothers at risk for abusing or neglecting their children. PARTICIPANTS: Seven first-time mothers, ages 13 to 20, who reported they had been abused and/or neglected as children. All had healthy newborns. RESULTS: Five themes emerged from the data: impoverished past, disintegration of relationships, emotional distance, problem fixing, and reconnecting. Participants described a process of using the experience of pregnancy and parenting as a mechanism for growth. Becoming a parent provided an opportunity to receive support from family members and to build more positive relationships. They viewed the experience as a second chance for a successful and fulfilling life.

Adaptation, Psychological↗
PubMedDate not supplied

Spyrosorb and Spyroflex.

With the numerous wound dressings now available, it is sometimes difficult to know which dressing is right for each different situation. This article examines the action of two products and highlights their appropriateness in varying circumstances.

Bandages↗
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Sorbsan.

Seaweed has been used since the 1800s in the treatment of wounds. Sorbsan is an alginate dressing designed to absorb large amounts of exudate. Sorbsan is removed by irrigation without causing damage to newly forming tissue. Sorbsan is a relatively painless dressing to remove.

Alginates↗
PubMedDate not supplied

Granuflex.

Granuflex has been used in wound management since the 1960s. The new improved formulation enables gel to be confined within the structure of the dressing, thus aiding the control of wound exudate. Granuflex is suitable for many types of chronic, acute and traumatic wounds. Granuflex fulfils many of the characteristics of the ideal dressing: it reduces pain, is less time-consuming, promotes rapid healing, is cost-effective, and is easy to use in practice. Granuflex plays an important role in infection control by protecting the wound from contamination and preventing the spread of infection.

Colloids↗
PubMedDate not supplied

Paediatric cardiopulmonary resuscitation.

A good knowledge of paediatric resuscitation procedures can instil confidence in the nurse faced with a critically ill child and can improve the outcome for that child. This article reviews both basic and advanced resuscitation procedures that are recommended for use in the paediatric age group.

Adolescent↗