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Biomedical subjects

A Fisher

Publications and source records attributed to A Fisher.

At least 127 records · Page 7Linked to original sources
PubMed1995

Use of think aloud method to study nurses' reasoning and decision making in clinical practice settings.

The purpose of this article was to describe the use of TA method to study nurses' reasoning and decision making in a neurosurgical setting. The feasibility and benefit of the method were explored, and examples were provided from data collected on a neurosurgical unit during the immediate post operative care of craniotomy patients. The authors hope that this report will encourage other investigators to consider using this method to examine nurses' reasoning and decision making. They also hope that future investigators will be encouraged to move TA to clinical practice settings, rather than continuing to rely on simulations, which can never fully replicate the realities of clinical practice.

Clinical Nursing Research↗
PubMed1995

Adhesion of flowing neutrophils to cultured endothelial cells after hypoxia and reoxygenation in vitro.

Using a novel in-line deoxygenating system linked to an in vitro flow-based adhesion assay and video microscopy, we have studied neutrophil recruitment and migration after hypoxia and reoxygenation of cultured human umbilical vein endothelial cells (HUVEC). Unstimulated purified neutrophils were perfused over reoxygenating HUVEC immediately after various periods of endothelial hypoxia. Adhesion to HUVEC was dependent on the duration of hypoxia, with 30, 60, and 100 min of exposure causing graded increments in neutrophil recruitment. The degree of hypoxia also markedly influenced the endothelial response. Severe hypoxia (O2 < 2.5%) induced stationary attachment and then migration of neutrophils, in contrast to rolling adhesion alone under a less intense regime (O2 = 2.5-4.0%). Judged from studies with monoclonal antibodies, P-selectin was essential for adhesion after severe hypoxia, and neutrophil immobilization was attributable to the activation of neutrophil beta 2-integrin. Perfusion of neutrophils with an antibody against interleukin-8 or a platelet-activating factor antagonist reduced levels of adhesion. However, IL-8 appeared to be the dominant agent involved in the immobilization from flow, whereas platelet-activating factor was the more potent agent involved in initiating subendothelial migration. Thus endothelial cells alone can initiate all stages of adhesion and migration of flowing neutrophils after hypoxia and reperfusion.

Cell Adhesion↗
PubMed1995

The ethical problems encountered in psychiatric nursing practice with dangerous mentally ill persons.

Psychiatric nursing practice in acute inpatient and emergency settings requires that practitioners identify and manage dangerous patients. The analyses reported here are part of a broader study that sought to understand how psychiatric nurses define and manage the dangerous mentally ill. This paper identifies three ethical problems encountered in the day-to-day practices of psychiatric nurses, as they cared for and managed the dangerous mentally ill. The three ethical problems, balancing support for patient autonomy with the need to maintain unit control; balancing the need for distancing with the desire to establish therapeutic relationships; and balancing the desire to "do the right thing" with the need to get along with colleagues, have implications for psychiatric nursing practice and the institutional settings that treat the dangerous mentally ill. Additionally, this study provides direction for further inquiry into the actual ethical problems encountered in practice.

Adult↗
PubMed1995

A multidisciplinary approach to hepatocellular carcinoma in patients with cirrhosis.

BACKGROUND: A multidisciplinary approach has been developed to evaluate and treat patients with cirrhosis and hepatocellular carcinoma (HCC). STUDY DESIGN: We evaluated 153 patients with cirrhosis and HCC. Fourteen patients with Child's A cirrhosis underwent resection. Transplantation was performed in 40 patients with HCC less than 5 cm (32 incidental, eight recognized preoperatively), in six patients with HCC 5 cm or greater not recognized preoperatively, and in 11 patients with recognized HCC 5 cm or greater; the latter 11 underwent transplantation in a multimodality protocol using pretransplant chemoembolization and intraoperative and postoperative chemotherapy. RESULTS: Among the 14 patients who underwent resection, the three-year survival rate was 39 percent. Among the 40 patients with HCC less than 5 cm who underwent transplantation, no tumor recurrence was observed. Among the six with HCC 5 cm or greater unrecognized preoperatively, three had tumor recurrence. Among the 11 with HCC 5 cm or greater enrolled in the protocol, there were no deaths and one recurrence at a mean of 433 days follow-up. The four-year survival rate for all patients who underwent transplantation with HCC was 56 percent (66 percent excluding the six patients with unrecognized HCC 5 cm or larger). CONCLUSIONS: Hepatocellular carcinoma less than 5 cm in patients with cirrhosis (Child's B or C) is an indication for hepatic transplantation. Hepatocellular carcinoma less than 5 cm in patients with cirrhosis (Child's A), although resectable, may in some cases be better treated by hepatic transplantation. Transplantation for HCC 5 cm or greater within a multimodality protocol has yielded excellent results at two years.

Aged↗
PubMed1995

An exploration of an innovative methodological approach for examining nurses' heuristic use in clinical practice.

What heuristics (reasoning strategies) do experienced critical care nurses use to assist in reasoning and making decisions about patient care? In this study, think aloud data were collected and protocol analysis was utilized to identify and describe the heuristics that permitted nurses to evaluate patient data, assess patient status, and make decisions necessary to maintain patient stability. Five heuristics were identified: pattern recognition, attending, anchoring, focused questioning, and listing. Clearer understanding of nurses' heuristic use could improve reasoning in practice, and could also provide educators with strategies to enhance the reasoning of their students.

Attention↗
PubMed1994

Discrete activation of transduction pathways associated with acetylcholine m1 receptor by several muscarinic ligands.

Activation of transfected muscarinic m1 acetylcholine receptors (m1AChR) has been linked to several signal transduction pathways which include phosphoinositide hydrolysis, arachidonic acid release and cAMP accumulation. In Chinese hamster ovary cells stably transfected with the rat m1AChR gene, carbachol elicited all three responses with EC50 values of 2.6, 3.8 and 76 microM, respectively. However, pilocarpine and the selective muscarinic agonist AF102B activated phosphoinositide hydrolysis (by 94 and 27% vs. carbachol, respectively), while antagonizing carbachol-mediated cAMP accumulation. Carbachol also activated (by 4-fold) adenylyl cyclase in membranes prepared from these cells, indicating independence of this signal from intracellular mediators. Moreover, carbachol and AF102B similarly elevated cytosolic Ca2+ in intact m1AChR-transfected cells. The ligand-selective cAMP accumulation, its independence from Ca2+ and the carbachol-activated adenylyl cyclase in membranes suggest that it represents an independent m1AChR-mediated signal, unrelated to phosphoinositide hydrolysis. Selective muscarinic ligands such as AF102B may independently activate distinct signalling pathways, which may be important for designing cholinergic replacement therapy for treating Alzheimer's disease.

Adenylyl Cyclases↗
PubMed1994

Interaction of HIV gp120 and anti-CD4 antibodies with the CD4 molecule on human CD4+ T cells inhibits the binding activity of NF-AT, NF-kappa B and AP-1, three nuclear factors regulating interleukin-2 gene enhancer activity.

The membrane glycoprotein CD4 is required for optimal antigen-mediated activation of CD4+ T cells restricted by class II molecules of the major histocompatibility complex (MHC). CD4 cross-linking by anti-CD4 antibodies or binding by human immunodeficiency virus (HIV) gp120 has been shown to inhibit antigen-dependent and -independent T cell activation, abrogating T cell proliferation, IL-2 synthesis and the increase in the intracellular calcium concentration. The molecular basis of these opposing phenomena is ill-defined. To characterize further the inhibitory role of the CD4 molecule, we investigated the effects of CD4 ligands on the transcription factors regulating the IL-2 gene enhancer and IL-2 synthesis. We first confirmed that pre-treatment of peripheral human CD4+ T lymphocytes by CD4 ligands, HIV gp120 or anti-CD4 monoclonal antibodies inhibited IL-2 production and cell proliferation, which was normally induced by an anti-CD3 antibody (UCHT1) plus a protein kinase C activator (PMA). Moreover, these CD4 ligands inhibited the proliferation and synthesis of IL-2 induced by activators bypassing membrane events, i.e. PMA and calcium ionophore, pointing to an active signaling pathway triggered by the CD4 molecule. Gp120 and anti-CD4 antibodies induced a specific, significant decrease in the binding activity of NF-AT, NF-kappa B and AP-1, three transcription factors regulating IL-2 gene enhancer activity, as demonstrated by electrophoretic mobility shift assays. Inhibition was similarly observed following cell activation by activators involving membrane events and those bypassing them. These results strongly suggest that the inhibition mediated by cross-linking of the CD4 molecule is at least partly due to negative signal down-regulating the availability of nuclear factors necessary for the regulation of IL-2 gene transcription.

Antibodies, Monoclonal↗
PubMed1994

Comparative studies of T = 3 and T = 4 icosahedral RNA insect viruses.

Crystallographic and molecular biological studies of T = 3 nodaviruses (180 identical subunits in the particle) and T = 4 tetraviruses (240 identical subunits in the particle) have revealed similarity in both the architecture of the particles and the strategy for maturation. The comparative studies provide a novel opportunity to examine an apparent evolution of particle size, from smaller (T = 3) to larger (T = 4), with both particles based on similar subunits. The BBV and FHV nodavirus structures are refined at 2.8 A and 3 A respectively, while the N omega V structure is at 6 A resolution. Nevertheless, the detailed comparisons of the noda and tetravirus X-ray electron density maps show that the same type of switching in subunit twofold contacts is used in the T = 3 and T = 4 capsids, although differences must exist between quasi and icosahedral threefold contacts in the T = 4 particle that have not yet been detected. The analyses of primary and tertiary structures of noda and tetraviruses show that N omega V subunits undergo a post assembly cleavage like that observed in nodaviruses and that the cleaved 76 C-terminal residues remain associated with the particle.

Crystallography, X-Ray↗
PubMed1994

Clinically significant mucosal candidiasis resistant to fluconazole treatment in patients with AIDS.

Eight cases of severe mucosal candidiasis in patients with AIDS who were taking fluconazole at a dosage of 400-800 mg/d are described. Candida albicans alone or in conjunction with Torulopsis glabrata or Candida stellatoidea was isolated from each patient. In vitro susceptibility testing demonstrated resistance to fluconazole in all eight cases. All tested isolates were susceptible to amphotericin B, and six of eight isolates tested were susceptible to itraconazole. All individuals were severely immunocompromised (CD4 lymphocyte counts: mean, 15/mm3; range, 6-39/mm3) and had been receiving prophylaxis with fluconazole for a mean of only 3 months (range, 1-7 months). The occurrence of candidal mucositis in patients receiving high doses of fluconazole is a matter of concern that requires further study in regard to the causes, prevention, and treatment of the disease.

AIDS-Related Opportunistic Infections↗
PubMed1994

The profile of IgG1 and IgG2a antibody responses in mice exposed to Schistosoma mansoni.

The segregation of IgG2a and IgG1 immunoglobulin isotypes as markers for Th1 and Th2 lymphocytes respectively, was investigated in mice exposed to normal or optimally-irradiated S. mansoni cercariae. Using a panel of ELISAs, soluble antigens from lung-stage schistosomula, adult worms, or eggs, were probed with serum samples collected at biweekly intervals. Infected mice developed increased IgG1 responsiveness to all three antigens, especially between weeks five and seven, whereas IgG2a responses were lower, particularly to egg antigens. This confirms that Th2 responses are dominant after the onset of patency in infected mice. In comparison, vaccinated mice developed lower levels of IgG1, and higher levels of IgG2a to larval and worm antigens. Thus, they had balanced expression of IgG1 and IgG2a, despite having a dominant Th1 lymphocyte population. An elevated IgG1 response to egg antigens in vaccinated mice challenged with normal parasites, occurred two weeks later than in normal mice. Mice exposed to male-only cercariae developed IgG1 and IgG2a antibodies to larval and worm antigens. However, they also had elevated IgG1 to egg antigens from week five, despite a total absence of eggs. Therefore, adult worm antigens may cross react with the egg and stimulate the switch to Th2 dominated responsiveness.

Animals↗
PubMed1994

One agency's use of risk assessment and risk communication.

Few organizations have the courage to evaluate their own use of risk assessment (identifying hazards and estimating their probability and magnitude) and risk communication (interacting with internal and external stakeholder groups about risks). The USDA Animal and Plant Health Inspection Service (APHIS) wants to enhance its overall risk analysis process for managing a wide range of risks to animals, plants, and human health. We gathered survey data for a baseline of APHIS professionals' understanding and use of risk assessment and risk communication. APHIS professionals spend a surprisingly large share of their time communicating about risks. They perceive that risk estimates influence decisions, but that risk estimates should have more influence. Respondents reported little opposition to APHIS risk management decisions, and little use of channels such as USDA Extension Service for disseminating risk messages. Substantial variance across responses is explained mostly by differences in the roles of the 11 work units (now 10) within the agency. Location also contributes to the variance. Demographic variables seem less important.

Communication↗
PubMed1994

Angiotensin receptor regulates cardiac hypertrophy and transforming growth factor-beta 1 expression.

The role of angiotensin II via the angiotensin type 1 or type 2 receptor in the development of cardiac hypertrophy was determined in adult male Sprague-Dawley rats subjected to coarctation of the abdominal aorta. Five groups of animals were studied: coarctation, coarctation plus DuP 753, coarctation plus PD 123319, sham plus DuP 753, or sham operation. Type 1 receptor blockade was accomplished with DuP 753 given in the drinking water and type 2 blockade with PD 123319 delivered by osmotic minipumps beginning with the day of surgery until 72 hours after aortic coarctation. Mean carotid blood pressures and the carotid-femoral artery blood pressure gradients were not different among coarctation, coarctation plus DuP 753, and coarctation plus PD 123319 animals. However, ratios of heart weight to body weight were higher in coarctation (4.95 +/- 0.8) or coarctation plus PD 123319 (4.52 +/- 0.5) than in sham animals (3.6 +/- 0.4; P < .005 and .05, respectively). In coarctation plus DuP 753-treated animals heart weight-body weight ratios were not different from sham or sham plus DuP 753 animals (3.9 +/- 0.4 versus 3.6 +/- 0.4 or 3.3 +/- 0.08, respectively). Type 1 receptor mRNA levels were significantly increased in the coarctation group, with the highest levels in the coarctation plus DuP 753 and sham plus DuP 753 groups. To determine whether growth factors were involved in the hypertrophic process, we measured transforming growth factor-beta 1 mRNA levels. Northern analysis demonstrated a twofold increase in coarctation animals compared with sham or coarctation plus DuP 753-treated animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin II↗