Search PubMed⌕ Search

Biomedical subjects

R Anderson

Publications and source records attributed to R Anderson.

At least 55 records · Page 3Linked to original sources
PubMed1997

Managed care: increased opportunities for acute-care nurse practitioners.

Significant changes in the health-care delivery system during the past few years has resulted in shifts in managed care. Under this system, the fundamental assumptions of health-care delivery have been challenged and are beginning to change: emphasis on health, not illness, primary versus specialty care, hospital-based care to care networks, and revision of medical education patterns. The resulting opportunity for nursing has assisted in the expansion of its care to a practitioner model within the acute-care setting. Through case management and direct acute-care patient management, acute-care nurse practitioners (ACNPs) may ultimately contribute to reductions in hospitalization costs. Literature suggesting actual costs of ACNPs to be high must be measured against their invaluable contributions to increased quality of care. Detailed evaluation programs are needed for more complete analysis. An example of ACNP practice at a large teaching hospital shows varied interpretations of the role.

Hospitals, Teaching↗
PubMed1997

Acetabular labrum tear in a 15-year-old male: diagnosis with correlative imaging.

A 15-year-old male with unresolved hip pain after minor trauma is presented. The diagnosis of an acetabular labral tear was made using correlative scintigraphic and magnetic resonance (MR) imaging, obviating the more invasive investigations of arthrography or arthroscopy of the hip. The clinical and radiological features of this lesion are reviewed. Undiagnosed, acetabular labral tears may result in considerable morbidity. Appropriate operative or conservative management of the condition usually provides symptomatic relief.

Accidental Falls↗
PubMed1997

Activation of endothelial cells via antibody-enhanced dengue virus infection of peripheral blood monocytes.

Although endothelial cells have been speculated to be a target in the pathogenesis of dengue hemorrhagic fever (DHF), there has been little evidence linking dengue virus infection to any alteration in endothelial cell function. In this study, we show that human umbilical vein endothelial cells become activated when exposed to culture fluids from dengue virus-infected peripheral blood monocytes. Maximum activation was achieved with culture fluids from monocytes in which virus infection was enhanced by the addition of dengue virus-immune serum, thus correlating with epidemiological evidence that prior immunity to dengue virus is a major risk factor for DHF. Activation was strongest for endothelial cell expression of VCAM-1 and ICAM-1. In contrast, activation of endothelial cell E-selectin expression appeared to be more transient, as indicated by its detection at 3 h, but not at 16 h, of treatment. Treatment of monocyte culture fluids with anti-tumor necrosis factor alpha (TNF-alpha) antibody largely abolished the activation effect (as measured by endothelial cell expression of ICAM-1), whereas treatment with IL-1beta receptor antagonist had a much smaller inhibitory effect on activation. Endothelial cells inoculated directly with dengue virus or with virus-antibody combinations were poorly infectable (compared to Vero cells or peripheral blood monocytes), and virus-inoculated endothelial cells showed no increased expression of VCAM-1, ICAM-1, or E-selectin. Taken together, the results strongly indicate that dengue virus can modulate endothelial cell function by an indirect route, in which a key intermediary is TNF-alpha released from virus-infected monocytes.

Adult↗
PubMed1997

Evaluation of social status as a contributing factor to the stroke belt region of the United States.

BACKGROUND AND PURPOSE: The southeastern United States has stroke mortality rates above the national average. The causes for this excess mortality are unknown; however, lower socioeconomic status (SES) is a risk factor for stroke, and the lower SES in the Southeast is a potential cause. In this report we assess the proportion of the excess stroke mortality attributable to SES. METHODS: The more than 400,000 participants in the National Longitudinal Mortality Study were categorized into three regions: the coastal plain region of North Carolina, South Carolina, and Georgia ("stroke buckle"); the remainder of these states plus five other southern states ("stroke belt"); and the remainder of the United States. The stroke mortality rates were calculated with and without adjustment for SES, and the proportion of the excess mortality attributable to SES was estimated. RESULTS: In persons between the ages of 35 and 54 years, stroke mortality in the stroke buckle is estimated to be more than twice that of the rest of the nation and 1.7 times greater for ages 55 to 74 years. For persons in the stroke belt, the stroke mortality was 1.3 times greater than that in the rest of the nation for the ages of 35 to 54 and 55 to 74 years. Less than 16% of this excess stroke morality was attributable to SES. CONCLUSIONS: SES does not appear to be a major contributor to the excess mortality in the southeastern United States. Of additional concern is the stroke buckle region, which was shown to have stroke mortality rates substantially greater than those in the traditionally recognized stroke belt.

Adult↗
PubMed1997

Impact of patch testing on dermatology-specific quality of life in patients with allergic contact dermatitis.

BACKGROUND: A dermatology-specific quality-of-life instrument has been created and validated for its sensitivity, reproducibility, content, and construct validity. This instrument was used in an observational prospective study that evaluated the cost-effectiveness of patch testing in patients with contact dermatitis and suspicion of allergic component. OBJECTIVE: This multicenter, prospective, observational study was designed to study the various direct and indirect costs associated with diagnosis and treatment of suspected allergic contact dermatitis and the benefits of diagnosis with and without patch testing. The costs and benefits of various methods of diagnosis are evaluated to determine if patch testing is more cost-effective as a diagnostic method. One of the outcomes evaluated was the quality of life of the participants in the study and the impact of patch testing on this cohort. METHODS: A total of 567 subjects were enrolled to obtain evaluable data from at least 500 subjects from ten study centers; the investigators were chosen so as to obtain a mix of stratified degrees of usage of patch testing. Data were collected on demographics, physical characteristics, history of disease, visits to physicians, and, to evaluate costs, the use of resources such as drugs, nondrug substances, and services; other outcome data collected were on physician evaluation of improvement, confirmation of diagnosis, physician opinion of the disease management, and patient evaluation of dermatology-specific quality of life (DSQL), and pertinent economic factors. Only 6-month and 12-month follow-up visits were mandatorily scheduled according to the protocol; however, participants and providers were free to arrange additional visits as deemed necessary for health care. RESULTS: This report focuses on the evaluations at the 6-month follow-up. There are completely evaluable data on pharmacoeconomics and DSQL for 431 patients. About 43% were patch tested, and the rest were diagnosed using the information from history and physical examinations. There was significantly better improvement in each of the DSQL domains in patch tested subjects compared with non-patch-tested subjects. In addition, patients treated in "low" use clinics had lower quality of life at 6-month follow-up than those treated in "high" use clinics. CONCLUSION: Patch testing helps to diagnose the etiology of contact dermatitis early and treat the disease before it becomes chronic, thus reducing resources used and improving patient quality of life considerably.

Case-Control Studies↗
PubMed1996

Leg proprioceptors of the tobacco hornworm, Manduca sexta: organization of central projections at larval and adult stages.

Organization of the central neuropil of the insect ganglion is characterized in part by a modality-specific layering of afferent projections. This organization has been particularly well described for the central projections of thoracic leg sensory neurons of adult locusts, crickets, and flies. Tactile sensory neurons project into a ventral layer of neuropil, while proprioceptive sensory neurons project into an intermediate layer of neuropil. In order to determine whether a modality-specific layering exists in the CNS of larval Manduca sexta, we have examined the projections of sensory neurons innervating one class of putative proprioceptors, the campaniform sensilla, of the larval metathoracic legs. We find that campaniform sensory neurons of the larval legs have central projection patterns that generally distinguish them from each other and from the tactile sensory neurons. The campaniform projections, however, are not completely segregated from tactile projections in ventral layers of neuropil, as has been described in other insects. By contrast, the projections of campaniform sensory neurons from the adult legs are more extensive and elaborate than their larval counterparts and dramatically different from projections of nearby adult tactile hairs, having extensive arborizations in more dorsal regions of neuropil while those of tactile sensory neurons are restricted to very ventral layers of neuropil. This difference in organization of the afferent projections in larval and adult ganglia may reflect different functions of the leg sensilla and different functions of the legs at the two stages.

Animals↗
PubMed1996

Membrane stabilizing, anti-oxidative interactions of propranolol and dexpropranolol with neutrophils.

We have investigated the effects of the beta-adrenoreceptor-blocking agent, propranolol (9-300 microM) on several pro-inflammatory activities of human neutrophils in vitro. Superoxide production by calcium ionophore (A23187)-activated neutrophils was particularly sensitive to inhibition by low concentrations (9-18.7 microM) of this drug. However, inhibition of superoxide generation by neutrophils activated with phorbol myristate acetate (PMA), opsonized zymosan (OZ), and arachidonate (AA) only occurred with higher concentrations of propranolol, and coincided with decreased intracellular calcium fluxes, phospholipase A2 (PLA2) activity and synthesis of platelet-activating factor (PAF). Propranolol possessed neither cytotoxic nor superoxide-scavenging properties but, using a haemolytic assay of membrane-stabilizing activity, this agent neutralized the membrane-disruptive effects of the bioactive phospholipids, lysophosphatidylcholine (LPC), PAF, and lysoPAF(LPAF). A mechanistic relationship between the anti-oxidative and membrane-stabilizing properties of propranolol was suggested by the observation that pretreatment of neutrophils with LPC or PAF eliminated the inhibitory effects of the drug on superoxide generation by PMA-activated neutrophils. Dexpropranolol, a stereoisomer with minimal beta-blocking activity, and propranolol were equally effective with respect to their membrane-stabilizing and anti-oxidative interactions with neutrophils, but several other beta-blocking agents (atenolol, metoprolol, sotalol, and timolol) did not possess these activities. Inhibition of oxidant generation is, therefore, not a common property of beta-blocking agents and, in the case of propranolol, appears to occur as a consequence of membrane-stabilization rather than by beta-receptor-directed effects.

Acridines↗
PubMed1996

FGF-2 influences cell movements and gene expression during limb development.

FGF-2 is proposed to be an important ectodermal signal directing limb outgrowth and patterning. Consistent with this hypothesis we show that ectopic application of FGF-2 can maintain the apical ectodermal ridge (AER)-dependent expression of Sonic hedgehog (Shh), and AER-dependent zone of polarizing activity (ZPA) signaling. We also find that ectopic FGF-2 applied to the posterior wing bud caused a dramatic change in the morphology of the limb bud, and results in limbs that display a reduction in the length of individual skeletal elements and loss of digits. Associated with these morphological changes was an FGF-2-stimulated expansion and bifurcation of the expression domains of two posteriorly expressed genes, Shh and HoxD13. Applying FGF-2 at a central or anterior location in the limb bud did not alter the Shh expression domain or cause digit loss. To test whether ectopic application of FGF-2 into the posterior limb bud was influencing the movement of limb bud cells, we used the lipophilic dye DiI to map the behavior of posterior cells in response to FGF-2. In response to FGF-2 posterior limb bud cells move in both a proximal and a distal direction, causing the initially labeled cell population to bifurcate into two distinct domains. Our data suggest that FGF-2 is influencing limb outgrowth by modifying cell movements and subsequent position-specific cell-cell interactions that are important for limb morphogenesis.

Animals↗
PubMed1996

Membrane-stabilizing, anti-inflammatory interactions of macrolides with human neutrophils.

The effects of the macrolide antimicrobial agents azithromycin, clarithromycin, erythromycin and roxithromycin on the prooxidative activity of stimulated human neutrophils have been investigated in vitro. Superoxide generation by activated neutrophils was measured by lucigenin-enhanced chemiluminescence. At the concentrations used (2.5-80 micrograms/ml) none of the test agents was cytotoxic, nor did they possess superoxide-scavenging properties. Treatment of neutrophils with all 4 macrolides was accompanied by dose-related inhibition of superoxide production by cells activated with FMLP or the calcium ionophore (A23187), while the responses activated by phorbol myristate acetate (PMA) or opsonized zymosan were minimally affected. The anti-oxidative interactions of roxithromycin with FMLP-activated neutrophils were neutralized by pretreatment of the cells with low, non-cytotoxic concentrations (0.5 microgram/ml) of the prooxidative, proinflammatory bioactive phospholipids, lysophosphatidylcholine (LPC), platelet-activating factor (PAF) and lyso-PAF (LPAF). Using an assay of membrane-stabilizing activity, the macrolides antagonized the membrane-disruptive effects of LPC, PAF and LPAF, without affecting enzymes involved in their synthesis. These membrane-stabilizing interactions of macrolides with neutrophils may counteract the proinflammatory, prooxidative activity of several bioactive lipids which have been implicated in the pathogenesis of bronchial asthma.

Adult↗
PubMed1996

Increased levels of autoantibodies to cardiolipin and oxidised low density lipoprotein are inversely associated with plasma vitamin C status in cigarette smokers.

In this study we have measured circulating levels of autoantibodies to cardiolipin and oxidised low-density lipoprotein (ox-LDL) and correlated these with plasma concentrations of the anti-oxidant nutrients vitamin C, vitamin E and beta-carotene, in a group (79) of asymptomatic, male cigarette smokers and in non-smoking control subjects. Cigarette smoking, a well-known risk factor for development of atherosclerosis, was found to be associated with moderately elevated levels of autoantibodies to both cardiolipin and ox-LDL. Increased levels of these autoantibodies were most evident in the older smokers (> 30 years) and were significantly and inversely correlated with plasma vitamin C, but not with vitamin E or beta-carotene. Absorption studies designed to investigate the specificity of these autoantibodies demonstrated a high degree of cross-reactivity of cardiolipin antibodies with ox-LDL, while antibodies to the oxidatively modified lipoprotein tended to be specific for this antigen. These findings suggest that cigarette smoking promotes formation of autoantibodies to both cardiolipin and ox-LDL and that these may be involved in the initiation and/or perpetuation of atherosclerosis. Dietary intake of vitamin C may be a determinant of susceptibility to development of this cardiovascular disorder.

Adult↗
PubMed1996

Morphologic changes in offspring of female mice exposed to ethanol before conception.

OBJECTIVE: Our purpose was to evaluate the mutagenic effects of preconceptional ethanol exposure by use of the mouse model. STUDY DESIGN: Fifty-three adult female CF-1 mice were divided into one of five groups with or without an ethanol diet for 28 days. Mice were then superovulated and mated. On day 14 of gestation all mice were killed and fetuses removed and examined for abnormalities. RESULTS: The mutation index for the study and mutagen groups was similar (48% vs 41%). The percentage of any anatomic abnormality in any treatment group were between 50% and 100%. Anomalies of the abdominal wall were most commonly seen in the mutagenic groups. CONCLUSIONS: Chronic ethanol exposure in the female mouse before conception yields anatomic abnormalities in the offspring. These mutagenic effects may be variable in that they may result in a dominant lethal mutation or a delayed interference with organogenesis. Ethanol consumption, whether before or after conception, poses an unfavorable outcome in the offspring produced.

Abnormalities, Drug-Induced↗
PubMed1996

Delivery of the Pertactin/P.69 polypeptide of Bordetella pertussis using an attenuated Salmonella typhimurium vaccine strain: expression levels and immune response.

Pertactin/P.69, a surface-associated polypeptide antigen of Bordetella pertussis, was expressed in a Salmonella typhimurium aroA aroD vaccine strain, BRD509, using different expression systems, and the immune response in mice against these constructs was compared. Initially, Pertactin/P.69 was expressed on the surface of BRD509 from a single copy of the gene encoding the antigen localized on the Salmonella chromosome. As previously shown, secretory and humoral antibody responses could not be detected following multiple immunization with this strain (BRD640). However, a strong anti-Pertactin/P.69 proliferative response was observed in murine splenocytes following a single oral dose with BRD640. The stimulated splenocytes secreted interferon-gamma but not interleukin-5, indicating that BRD640 induced a Th1 type T-helper response against Pertactin/P.69. We wished to construct a vaccine strain that might induce secretory and humoral responses against Pertactin/P.69 as well as a cell-mediated immune response. Consequently, Pertactin/P.69 was expressed at high levels in the cytoplasm of BRD509 under the control of the inducible nirB promoter from a ColE1-based replicon. Anti-Pertactin/P.69 immune responses were not observed following immunization of BALB/c mice with this strain (BRD975). Priming of the immune system against Pertactin/P.69 was, however, observed following oral immunization with BRD975 and boosting subcutaneously with purified Pertactin/P.69 antigen. The major anti-Pertactin/P.69 IgG subclass detected in boosted mice was IgG2a; thus, as BRD640, BRD975 appeared to induce a Th1 type T-helper response against Pertactin/P.69.

Animals↗
PubMed1996

Bonesetters and curers in a Mexican community: conceptual models, status, and gender.

In the indigenous Mexican village of Hueyapan, there is a clear contrast between the supernatural beliefs curers use to explain illness and the naturalistic assumptions made by this community's bonesetters. In addition to employing different conceptual models, the two types of healers differ with respect to their manner of recruitment, training, types of illnesses treated, social status, and gender. These differences add up to a seeming enigma: in a community where men largely control political, economic, and religious affairs, the higher status role of curer is undertaken most frequently by women and the lower status specialty of bonesetter by men. Hueyapan's health care system becomes less problematical, however, when it is recognized that recruitment to the bonesetter and curer roles is shaped by pragmatic considerations of role continuity and compatibility independent of the social status of these two occupations.

Female↗