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Biomedical subjects

G Reed

Publications and source records attributed to G Reed.

At least 19 recordsLinked to original sources
PubMed2001

Peripheral arterial responses to treadmill exercise among healthy subjects and atherosclerotic patients.

UNLABELLED: BACKGROUND-Peripheral cutaneous vascular beds, such as the fingertips, contain a high concentration of arteriovenous anastomoses, richly innervated by a-adrenergic nerve fibers, to control heat regulation. Nevertheless, for a variety of technical reasons, finger blood flow responses to exercise have not been well studied in health and disease. Hence, we compared finger pulse-wave amplitude (PWA) responses to exercise among 50 normal volunteers and 57 patients with atherosclerotic coronary artery disease (CAD) using a robust, modified form of volume plethysmography. METHODS AND RESULTS: PWA was quantified for each minute of exercise as a ratio relative to baseline. Exercise PWA responses were compared with clinical, hemodynamic, ECG, and myocardial single photon emission computed tomography parameters. Among normal subjects, 38 (76%) manifested vasodilation throughout exercise and 12 (24%) manifested initial vasodilation followed by vasoconstriction at high heart rate thresholds. None manifested vasoconstriction throughout exercise. By contrast, 20 CAD patients (35%) manifested progressive vasoconstriction from the onset of exercise, and 10 others (18%) manifested vasoconstriction at low heart rate thresholds (P < 0.001 versus normals) after initial vasodilation with exercise. Patients exhibiting vasodilation versus vasoconstriction during exercise had similar clinical and exercise profiles, except for a greater use of ACE inhibitors and a greater level of achieved metabolic equivalents among the former (P<0.05 for both). CONCLUSIONS: Half of our CAD patients manifested diminution in PWA that was consistent with peripheral arterial vasoconstriction during the early phases of treadmill exercise. Such paradoxical vasoconstrictive responses were not observed in normal subjects and, therefore, they may represent generalized vascular pathology secondary to atherosclerosis.

Adult↗
PubMed2001

Planning for a multi-imaging center picture archiving and communications system.

There are fundamental differences in planning and configuring a picture archiving and communications system (PACS) for a multisite imaging practice as compared to a hospital-based radiology department. In the for-profit, multi-imaging center environment, return on investment is more critical and the distributed nature of radiology operations presents complex communications, infrastructure, archiving, workflow, and distribution requirements. This article discusses desired outcomes for a multi-imaging center PACS and the planning, functional, technical, and support requirements necessary to achieve those outcomes.

Ambulatory Care Facilities↗
PubMed2001

Ypel1: a novel nuclear protein that induces an epithelial-like morphology in fibroblasts.

BACKGROUND: Embryonic development depends on the regulation of cell morphology and behaviour to carry out morphogenesis. One example of this is the development of the face, which is constructed from independent blocks of tissue that must grow in a coordinated way and then fuse to form a continuous tissue. RESULTS: We have isolated a novel gene of unknown function from mouse and quail embryos in a search for genes involved in craniofacial development. Sequence analysis of this gene, known as Ypel1, demonstrates a striking level of amino acid conservation between vertebrates and invertebrates but no significant homology with any other characterized genes. Ypel1 is expressed in the ventral half of early embryos including the branchial arches from which the face derives. Ypel1 localizes to the nucleus, and transfection into fibroblasts induces an epithelial-like transition, which is accompanied by alterations to the cytoskeleton and cell adhesion machinery. In addition, human YPEL1 localizes to chromosome 22q11.2, a region associated with a number of syndromes involving malformation of the craniofacial complex. CONCLUSION: These data suggest a role in regulation of cellular morphology and behaviour that is important for development of the craniofacial complex.

Amino Acid Sequence↗
PubMed2001

Variability and classification accuracy of serial high-sensitivity C-reactive protein measurements in healthy adults.

BACKGROUND: Increased concentrations of high-sensitivity C-reactive protein (hs-CRP), a marker of systemic inflammation, are associated with increased risk for coronary heart disease. Because of its relationship to inflammation, hs-CRP has considerable biologic variation. This study was carried out to characterize CRP variation and to compare it to another risk factor, total serum cholesterol. METHODS: One hundred thirteen individuals were scheduled to have five measurements each of hs-CRP and total cholesterol carried out at quarterly intervals over a 1-year period. Variations of hs-CRP and total cholesterol were characterized, and classification accuracy was described and compared for both. RESULTS: The relative variation was comparable for hs-CRP and total cholesterol. When classified by quartile, 63% of first and second hs-CRP measurements were in agreement; for total cholesterol it was 60%. Ninety percent of hs-CRP measurements were within one quartile of each other. This relationship was not altered by the use of log-transformed hs-CRP data. CONCLUSION: hs-CRP has a degree of measurement stability that is similar to that of total cholesterol.

Adult↗
PubMed2000

Presenilin 2 expression in neuronal cells: induction during differentiation of embryonic carcinoma cells.

Mutations in the presenilin 1 and 2 (PS1 and PS2) genes cause most cases of early onset Alzheimer's disease. The genes encode two homologous multipass membrane proteins. Since the endogenous expression of PS2 has been poorly analyzed to date, we studied PS2 expression and localization in cultured human neuroblastoma cells and mouse neuronal cells. PS2 was mainly detected as a full-length protein of about 52 kDa in these cells and in brain, in contrast to PS1 that is mainly detected as endoproteolytic N-terminal and C-terminal fragments. Using immunofluorescence we found that like PS1, PS2 colocalized with markers of the endoplasmic reticulum-Golgi intermediate compartment, ERGIC-53 and beta-COP. Double labeling for PS1 and PS2 indicated that both proteins are colocalized in neuroblastoma SH-SY5Y cells. To study PS2 expression during differentiation, mouse embryonic carcinoma P19 cells were treated with retinoic acid. We found minimal PS2 expression in undifferentiated cells, an increase from day 2, and a maximum at day 8 after treatment. PS1 expression remained constant during this period. The differential expression of PS1 and PS2 within the P19 cells following retinoic acid treatment indicates different utilization or temporal requirements for these proteins during neuronal differentiation.

Alzheimer Disease↗
PubMed2000

Immune-recovery uveitis in patients with cytomegalovirus retinitis taking highly active antiretroviral therapy.

PURPOSE: To investigate the clinical features associated with immune recovery in human immunodeficiency virus (HIV)-infected patients with cytomegalovirus retinitis who are taking highly active antiretroviral therapy. METHODS: Sixteen patients were evaluated prospectively at the National Eye Institute, Bethesda, Maryland. Evaluation included a medical history and a complete ophthalmologic examination. The examination included best-corrected visual acuity score measured by means of logarithmic charts, slit-lamp biomicroscopy, dilated retinal examination, retinal photography, and fluorescein angiography. Immune-recovery uveitis was defined as the ocular inflammation associated with clinical immune recovery in patients taking potent antiretroviral regimens. The ophthalmic characteristics of immune-recovery uveitis were identified, and their effect on visual acuity was statistically analyzed. RESULTS: The mean CD4+ T-lymphocyte count for the 16 patients taking highly active antiretroviral therapy at the time of evaluation was 393 cells/microl (range, 97-1,338 cells/microl). Immune-recovery uveitis was characterized by vitreitis and optic disk and macular edema. Clinically important complications of immune-recovery uveitis included cataract and epiretinal membrane formation. The visual acuity scores were significantly worse in the 23 eyes with cytomegalovirus retinitis (mean, 67.2 letters, 20/50) than in the nine eyes without cytomegalovirus retinitis (mean, 89.8 letters, 20/16) (P <.001). Regression analysis showed that a lower visual acuity score was associated with the presence of moderate to severe macular edema on fluorescein angiography and vitreous haze (P < or =. 001). CONCLUSIONS: Immune-recovery uveitis is an important cause of visual morbidity in HIV-infected patients with cytomegalovirus retinitis in the era of highly active antiretroviral therapy. Although immune recovery associated with highly active antiretroviral therapy has allowed some patients to discontinue specific anticytomegalovirus therapy, the rejuvenated immune response can be associated with sight-threatening inflammation.

AIDS-Related Opportunistic Infections↗
PubMed2000

Sequence and seasonal effects of salivary cortisol.

Assessments of cortisol levels in saliva have been widely used by both researchers and clinicians as an index of adrenal functioning. Quarterly measurements of morning and evening cortisol levels were determined in a longitudinal study of 147 participants (72 women and 75 men) followed for 1 year each. The analysis of salivary cortisol revealed no significant gender or age differences in the sample. There was a sequence effect in quarterly cortisol values with a progressive decrease in serial measurements, especially notable in the morning values; as well as a seasonal variation in cortisol levels with significantly higher levels found in winter and fall, compared with spring and summer. The findings in this study suggest that repeated saliva sampling and seasonal variation in cortisol levels may independently affect adrenal response and, therefore, need to be accounted for in longitudinal studies.

Adult↗
PubMed1999

Multiformic modulation of endotoxin effects by linomide.

Linomide is a potent immunomodulator that either enhances or suppresses certain immunological processes. Of particular interest is this compound's capacity to inhibit a variety of organ-specific autoimmune diseases. Here, we report on the effects of linomide on several immunological reactions elicited by endotoxin (LPS), both in vivo and in vitro. In rats and mice linomide inhibited the elicitation of endotoxin-induced uveitis (EIU), an acute inflammatory eye disease that develops within 24 h following footpad injection of LPS. Linomide also inhibited the production of TNF-alpha and IL-6 by LPS-stimulated rat and mouse macrophage monolayers. On the other hand, treatment with linomide significantly increased the levels of IL-1beta (mice and less in rats), IL-6 (rats), and TNF-alpha (mice) in serum samples collected 2 h following injection with LPS. The increased production of proinflammatory cytokines in linomide-treated mice was also indicated by the enhanced lethal effect of LPS in these mice. The finding of elevated levels of these cytokines in animals with suppressed EIU is also in line with previous observations of an inverse relationship between EIU severity and levels of TNF-alpha. Data recorded here underscore the unique capacity of linomide to both enhance and suppress the immune system.

Adjuvants, Immunologic↗
PubMed1999

Experience measuring performance improvement in multiphase picture archiving and communications systems implementations.

When planning a picture archiving and communications system (PACS) implementation and determining which equipment will be implemented in earlier and later phases, collection and analysis of selected data will aid in setting implementation priorities. If baseline data are acquired relative to performance objectives, the same information used for implementation planning can be used to measure performance improvement and outcomes. The main categories of data to choose from are: (1) financial data; (2) productivity data; (3) operational parameters; (4) clinical data; and (5) information about customer satisfaction. In the authors' experience, detailed workflow data have not proved valuable in measuring PACS performance and outcomes. Reviewing only one category of data in planning will not provide adequate basis for targeting operational improvements that will lead to the most significant gains. Quality improvement takes into account all factors in production: human capacity, materials, operating capital and assets. Once we have identified key areas of focus for quality improvement in each phase, we can translate objectives into implementation requirements and finally into detailed functional and performance requirements. Here, Integration Resources reports its experience measuring PACS performance relative to phased implementation strategies for three large medical centers. Each medical center had its own objectives for overcoming image management, physical/geographical, and functional/technical barriers. The report outlines (1) principal financial and nonfinancial measures used as performance indicators; (2) implementation strategies chosen by each of the three medical centers; and (3) the results of those strategies as compared with baseline data.

Benchmarking↗
PubMed1999

Serious maternal morbidity after childbirth: prolonged hospital stays and readmissions.

OBJECTIVE: To determine the frequency of and risk factors for serious morbidity resulting in a prolonged hospital stay or readmission among women enrolled in Tennessee's Medicaid program who delivered live or dead infants in 1991. METHODS: This retrospective cohort study included 33,251 women of white or black ethnicity. Main outcome measures included childbirth-related medical conditions serious enough to result in death, prolonged delivery hospitalization, or readmission within 60 days of delivery. RESULTS: Among 25,810 women with vaginal (78%) and 7441 (22%) women with cesarean deliveries, 2.6% and 8.9%, respectively, had at least one childbirth-related medical condition requiring prolonged delivery hospitalization or readmission, including infection (1.8% and 7.9%), hypertension-related complications (0.7% and 2.0%), or hemorrhage (0.5% and 2.4%). After controlling for other risk factors, maternal age over 32 years was independently associated with increased rate of serious morbidity among women who had vaginal (relative risk [RR] 1.9, 95% confidence interval [CI] 1.4, 2.7) or cesarean deliveries (RR 1.6, 95% CI 1.1, 2.2). Black women had approximately twice the rate of maternal morbidity with vaginal (RR 1.9, 95% CI 1.5, 2.4) or cesarean deliveries (RR 2.3, 95% CI 1.9, 2.9). Primiparous women who had vaginal or cesarean deliveries had a 60% (RR 1.6, 95% CI 1.3, 2.0) and 70% (RR 1.7, 95% CI 1.4, 2.0), respectively, greater risk of serious maternal morbidity than women with 1-3 prior births. CONCLUSION: Predictors of serious maternal morbidity included age over 32 years, black ethnicity, and primiparity.

Adolescent↗
PubMed1999

Asthma quality of life in a Southern practice: towards a new paradigm.

BACKGROUND: Quality of life (QOL) surveys are increasingly recognized as part of state-of-the-art asthma assessment. Disease-specific surveys quantitate total QOL and subscale domains which, along with changes in these measures, suggest asthma severity and effects of intervention. OBJECTIVES: This study was conducted to (1) compare regional variation in QOL and change in QOL in an allergy practice in the South and (2) to examine if one or a set of questions relating to asthma severity could estimate QOL thereby obviating the need for a complete survey. METHODS: Fifty-eight patients were administered an asthma specific quality of life (AQOL) questionnaire, the Marks et al Asthma Quality of Life survey, at baseline and surveyed in follow-up at 1 and 6 months. Additional questions were asked concerning bronchodilator use in a day and 1 week, missed work/school days, nocturnal wakening in 1 week due to asthma, emergency room visits in the previous month, and past hospitalizations in the last year. Spirometry was performed at each visit. RESULTS: Baseline AQOL is significantly (P < .05) related individually to nocturnal wakening, bronchodilator use in a day, work or school days missed, and hospitalization during the past year. A model combining these factors explains 49% of the variance, r2 = .49. The AQOL score between baseline and the first month shows a significant improvement (P < .0001) and this improvement is related (P = .002) to the reduction in nocturnal wakenings during that same time period. CONCLUSIONS: Specialty care intervention affected QOL similarly in the Southern practice compared with other regions/countries. Nocturnal wakening, bronchodilator use in a day, workdays missed, and hospitalization in the past year were all significantly correlated with AQOL. Number of nocturnal wakenings and bronchodilator use in a day may not only stratify asthma severity, they roughly stratify AQOL. The wide scatter of AQOL scores for a given indicator of asthma severity makes a limited combination of questions an indicator but not yet a reliable predictor of AQOL.

Asthma↗
PubMed1999

Thromboembolic complications of cardiac radiofrequency catheter ablation: a review of the reported incidence, pathogenesis and current research directions.

INTRODUCTION: Radiofrequency catheter ablation (RFCA) has become established as an effective therapy for the treatment of many cardiac tachyarrhythmias. The principle limitation of conventional RFCA continues to be the risk of thromboembolism. This risk is of particular concern for the ongoing development of the catheter maze procedure for the treatment of atrial fibrillation, which currently involves the creation of extensive linear lesions in the left atrium. METHODS AND RESULTS: A Medline search of the literature over the last ten years was performed. Focused review of the reported thromboembolic complications of RFCA indicates an overall incidence of 0.6%. However, the risk is increased when ablation is performed in the left heart (1.8% to 2%) and for ventricular tachycardia (2.8%). It is of concern that intravenous heparin and the use of temperature feedback to control radiofrequency current do not eliminate the risk of thromboembolic events. CONCLUSION: The thromboembolic complications of RFCA are not eliminated by the treatment of intravenous herapin and mode of temperature control during ablation. Potential approaches to further reduce the risk of thromboembolism include the adjunctive administration of specific inhibitors of platelet activation and aggregation, intraprocedural intracardiac echocardiography, irrigated radiofrequency ablation, and cryoablation catheter systems.

Anticoagulants↗
PubMed1999

Neurite-outgrowth regulating functions of the amyloid protein precursor of Alzheimer's disease.

Many studies have shown that breakdown of the amyloid protein precursor (APP) to produce the amyloid protein is an important step in the pathogenic mechanism which causes Alzheimer's disease (AD). However, little is known about the normal function of APP. Developmental studies show that APP expression increases during the period of brain development when neurite outgrowth and synaptogenesis is maximal. APP is expressed highly within growing neurites and in growth cones, and purified APP has been shown to stimulate neurite outgrowth from cells in culture. Thus APP may regulate neurite outgrowth or synaptogenesis in vivo. APP is actively secreted from many cells, and the C-terminally secreted APP has been shown to associate with components of the extracellular matrix, such as the heparan sulphate proteoglycans (HSPGs). Two putative heparin-binding domains on APP have been reported. Binding of HSPGs to an N-terminal heparin-binding domain (HBD-1) stimulates the effect of substrate-bound APP on neurite outgrowth. In the mature nervous system, APP may play an important role in the regulation of wound repair. It is highly likely that studies on the normal functions of APP will shed further light on aspects of the pathogenesis of AD.

Journal Article↗