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S Underwood

Publications and source records attributed to S Underwood.

14 recordsLinked to original sources
PubMed2000

Low concentrations of fibrinogen increase cell migration speed on fibronectin/fibrinogen composite cables.

Optimal cell migration rate in a given direction (velocity) is a function of speed and directional persistence. Migration speed has been reported to be a function of adhesion strength such that optimal cell migration occurs where the cell is able to form enough stable attachments for good traction while allowing attachments at the trailing end to be broken during locomotion. This is particularly important in peripheral nerve regeneration where rapid Schwann cell recruitment across the injury site will lead to better functional recovery and reduced end organ atrophy. The aim here was to investigate the effects of changing adhesion properties of Fn materials by adding fibrinogen in order to design an optimal material for repair processes. Cell migration on Fn/Fg-cables increased with increasing content of %Fg to a peak cell migration velocity (Schwann cells) of 49 microm/h, at 50% Fg. Further increases in Fg content hindered cell migration. Vinculin-rich attachment plaques were reduced in a dose-dependent manner as the content of %Fg was increased whilst cells at the optimum Fg proportion for cell migration were moderately well spread. These results support the idea that optimum cell migration rates occur at intermediate attachment conditions, in this case at 50% Fg. These results show that incorporation of Fg into Fn-based materials will enhance the speed of Schwann cell migration and this would be likely to improve peripheral nerve regeneration. Indeed, directionally aligned Fn-based materials can now be engineered to give optimal cell velocity during repair cell recruitment in a range of tissue repair or tissue engineering applications.

Animals↗
PubMed1998

Calprotectin and lactoferrin levels in the gingival crevicular fluid of children.

The purpose of this study was to determine the levels of calprotectin and lactoferrin, 2 microbiostatic proteins, in the gingival crevicular fluid (GCF) of normal children. The children represented a population, primarily underprivileged, seeking care at a regional dental health care center. GCF was collected from Ramfjord teeth (or their deciduous equivalent). GCF volume was quantified by conductance. Calprotectin and lactoferrin levels were quantified by sandwich ELISA, and found to have a mean value of 70.8+/-94.2 microg/mL and 68.2+/-108.7 microg/mL, respectively. The levels of calprotectin and lactoferrin varied directly with one another and inversely with the amount of fluid obtained in a 20-second sampling period. The mean levels were at or above the minimum inhibitory concentration determined in vitro.

Adolescent↗
PubMed1997

Infant feeding practices of low-income African American women in a central city community.

It is a well-established fact that nutrition is central to the growth and development of all infants. Yet it has been observed that health care professionals are frequently unfamiliar with the most typical infant feeding practices of the clients within the communities they attempt to serve. This observation was apparent during the development of a program in an inner-city community of Wisconsin to support the feeding practices of low-income African American women with low-birth-weight infants. As a result of initial encounters with prospective clients and health care and social service professionals from the targeted community, it was apparent that professionals and staff involved in this project needed to gain an understanding of common infant feeding practices of low-income African American women; a greater awareness of the values, beliefs, and health care practices of the population; and a greater understanding of the impact of poverty on the families within the targeted community. To assist the staff in gaining a better understanding of the influence of culture and economics on infant feeding practices, a study of the infant feeding practices of a select group of low-income African American women was undertaken. The study aimed to (a) gather information that could be used to describe common infant feeding practices of low-income African American women in an inner-city community of Wisconsin and (b) determine the influence of cultural and economic variables on the decisions made by low-income African American women regarding infant feeding. This article presents an analysis and summary of the data collected during the course of the study.

Adult↗
PubMed1995

Time-course of antigen-induced airway inflammation in the guinea-pig and its relationship to airway hyperresponsiveness.

The causative relationship between airway inflammation and hyperreactivity is unclear, since inflammatory changes have been examined at one or, at most, a few time-points after antigen challenge in both human asthma and animal models. We have made a detailed investigation of inflammatory and functional changes in the airways up to 8 days after antigen challenge in guinea-pigs. In particular, we examined the hypothesis that eosinophil-derived mediators contribute to tissue damage and the development of airway hyperresponsiveness. Following antigen challenge, the influx of inflammatory cells and mediator release in airway tissue and bronchoalveolar lavage fluid were correlated temporally with histopathological changes in airway tissue and airway responsiveness. Eosinophil influx was demonstrable at 4 h. Eosinophilia peaked after 24 h and persisted for at least 8 days. Parallel increases in the concentrations of major basic protein and eosinophil cationic protein in bronchoalveolar lavage fluid indicated that the eosinophils were activated. Eosinophilia was accompanied by subepithelial oedema and epithelial damage co-localized with major basic protein immunoreactivity. A transient neutrophilia (< 48 h duration) and an increase in neutrophil elastase in bronchoalveolar lavage fluid peaked at 14 h. The proportion of airway macrophages with an activated morphology increased at 8 h and remained markedly elevated until 72 h. Airways were hyperresponsive to histamine at 4 h and for at least 8 days. The antigen-induced airway inflammation resemble in time-course and histopathology that seen in antigen-challenged asthmatics, and indicate that the eosinophil and its cytotoxic proteins may be major mediators of airway mucosal damage and airway hyperresponsiveness.

Aluminum Hydroxide↗
PubMed1994

Propofol as sole agent for paediatric day-case dental surgery. A randomised study comparing an intravenous propofol infusion with 100% inspired oxygen versus a nitrous oxide/oxygen/halothane maintenance technique.

After intravenous induction of anaesthesia with propofol (4 mg.kg-1) 80 unpremedicated children admitted for day-case dental extractions were randomly allocated to receive either an intravenous propofol infusion whilst breathing 100% oxygen, or inhalational nitrous oxide, oxygen and halothane for maintenance of anaesthesia. In both groups, the quality of anaesthesia was acceptable to both anaesthetist and surgeon. Recovery times and postoperative analgesia requirements did not differ significantly between the two groups. No child vomited. Propofol appears to be suitable for use as a sole agent in paediatric day case dental surgery.

Anesthesia, Dental↗
PubMed1991

Pulmonary oedema following relief of upper airway obstruction in the Pierre-Robin syndrome: a consequence of early palatal repair?

Pulmonary oedema occurred following relief of an acute upper airway obstruction in an infant with Pierre-Robin syndrome undergoing cleft palate repair. We anticipate an increased prevalence of this phenomenon in view of the present trend for early palatal repair, and would advocate the routine use of a nasopharyngeal airway after operation in infants with severe micrognathia.

Airway Obstruction↗
PubMed1989

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Allied Health Personnel↗
PubMed1980

Beta adrenergic receptors of polymorphonuclear particulates in bronchial asthma.

We have tested the beta adrenergic receptor theory of bronchial asthma by determining the number and affinity of binding sites of the beta adrenergic radioligand [(3)H]dihydroalprenolol (DHA) and the activity of adenylate cyclase in broken cell preparations of polymorphonuclear leukocytes (PMN). We studied 31 control subjects (group 1), 30 asthmatics receiving no systemic adrenergic medication (group 2), and 17 asthmatics receiving adrenergic agonists systemically (group 3). Control subjects and asthmatics taking no adrenergic drugs bound similar amounts of DHA at 0.5 nM and 30 nM DHA and had about 900 binding sites per PMN. In contrast, asthmatics receiving adrenergic agonists had a >70% decrease in their number of DHA binding sites per PMN (254+/-57). In a subset of our three groups of subjects (eight from group 1, six from group 2, and five from group 3) we measured DHA binding at several DHA concentrations and found similar values (0.4-0.7 nM) for the dissociation constant of DHA among these subjects. In further studies we examined the interaction of the agonist (-)-isoproterenol with beta adrenergic receptors in 8 normal subjects and 10 asthmatics not receiving adrenergic medication. We tested the ability of isoproterenol to compete for DHA binding sites and to stimulate adenylate cyclase in sonicates prepared from PMN and examined under identical conditions. The dissociation constants for the competition of isoproterenol for DHA binding sites in normal and asthmatic subjects were virtually identical ( approximately 1.0 muM). In addition, the (activation constant) values for stimulation of adenylate cyclase were similar (0.16-0.19 muM) in the two groups of subjects.Thus, these data suggest that asthma per se is not associated with alteration in either the number or affinity of beta adrenergic receptors in PMN. Our findings indicate that previous reports of abnormal beta adrenergic receptor function in asthmatic patients may in part be explained by prior treatment of such patients with adrenergic agonists. Because the asthmatics who received adrenergic agonists in our study tended to be more ill and to receive additional medication compared to subjects in group 2, we cannot rule out unequivocally that severe asthma may be associated with decreased binding to beta adrenergic receptors. Nevertheless, we conclude that beta adrenergic receptors on PMN from asthmatics are relatively normal unless such patients are treated with adrenergic agonists.

Adenylyl Cyclases↗
PubMed1979

Beta adrenergic receptor binding on polymorphonuclear leukocytes in atopic dermatitis.

It has been postulated that the patient with atopic dermatitis has defective beta adrenergic receptor function. However, a more generalized defect is suggested by the observation that cyclic AMP generation is diminished in these patients following stimulation with both isoproterenol and PGE1. To determine the nature of this abnormality, we measured beta adrenergic receptor binding directly on polymorphonuclear leukocyte membranes using the radiolabeled beta adrenergic antagonist (-) [3H]dihydroalprenolol (DHA). DHA binding was studied in 6 mild and 9 moderate-to-severe atopic dermatitis patients, and 8 normal controls using a subsaturating concentration of DHA (0.5 nM) to estimate receptor affinity and a saturating concentration of DHA (30 mM) to determine the total number of receptors per cell. No significant differences (p greater than .05) were found in the total number of receptors per PMN between the control population (805 +/- 95) and the mild atopic dermatitis patients (745 +/- 91) or the moderate to severe group (621 +/- 79). In addition, no significant differences in receptor affinity were found among any of the 3 study groups. These findings suggest that beta receptor binding in atopic dermatitis is normal. Reduced cyclic AMP generation in atopic dermatitis PMN leukocytes would appear to be due to a defect distal to the beta adrenergic receptor itself.

Adult↗
PubMed1978

Characterization of high-affinity beta2-adrenergic receptor binding of (-)-[3H]-dihydroalprenolol to human polymorphonuclear cell particulates.

Human PMNs have well-described responses to beta-adrenergic catecholamines; these include elevation of cellular levels of cyclic AMP and inhibition of the release of lysosomal contents. Using the radioactive beta-adrenergic antagonist (-)-[3H]DHA in direct ligand-binding studies, we have identified and characterized beta-adrenergic receptors on particulate preparations of PMNs. These particulates bind DHA rapidly (t1/2 less than 1 min) and reversibly (t1/2 = 8 to 9 min). DHA binding is saturable and of high affinity (dissociation constant = 1 to 5 nM) and low capacity (870 +/- 128 receptors/cell, mean +/- S.D.) to a single class of binding sites. Competition for DHA binding sites by both beta-adrenergic agonists and antagonists is stereoselective [(-)-isomers more potent that (+)-isomers]. The rank order of potency of adrenergic agents in such competition studies indicates that these receptors are of the beta2 type. Since PMNs can be obtained in high purity with relative ease, the combined use of pharmacologic and ligand-binding studies in PMNs provide a useful system for studying beta-adrenergic receptors and their function in human subjects.

Adult↗
PubMedDate not supplied

Quality of life and the cancer experience: the state-of-the-knowledge.

PURPOSE/OBJECTIVES: To address the state-of-the-knowledge concerning quality of life (QOL) issues and the cancer experience from theoretical, research, clinical, and educational perspectives. DATA SOURCES: Published books and articles and a panel of experienced QOL experts who convened at the Oncology Nursing Society's State-of-the-knowledge Conference on Quality of Life in February 1995. DATA SYNTHESIS: Despite the evolution and support of QOL in oncology nursing practice, education, and research, there remains gaps in theory, research, and practice related to QOL. This article explores these gaps in knowledge and recommends future directions for QOL theory, research, education, and practice. CONCLUSIONS: Further conceptual work and resolution of QOL methodologic issues to guide clinical practice and education are warranted. The impact of cultural variables and precancer life experiences on patients' perceptions of QOL also must be addressed. NURSING IMPLICATIONS: Oncology nurse clinicians, educators, and researchers must continue to work collaboratively to enhance the knowledge base regarding QOL and to improve the nursing care provided to individuals with cancer.

Adolescent↗