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Biomedical subjects

D Dunn

Publications and source records attributed to D Dunn.

At least 37 records · Page 2Linked to original sources
PubMed1998

Correction of the PNH defect by GPI-anchored protein transfer.

Hemolytic anemia is a major feature of paroxysmal nocturnal hemoglobinuria (PNH). Intravascular red blood cell (RBC) destruction is caused by increased sensitivity of the abnormal erythrocyte to complement-mediated lysis, due to the GPI absence of a membrane-bound glycosylphosphatidylinositol (GPI)-linked protein, which functions as an inhibitor of reactive lysis (CD59). Both in vivo and in vitro models have suggested the feasibility of cell-to-cell transfer of GPI proteins, and patients with hemolysis could potentially benefit from transfer of CD59 to their deficient erythrocytes. We studied the ability of RBC components prepared from outdated packed RBC collections, as well as high-density lipoprotein (HDL) preparations, rich in CD55 and CD59, to promote protein transfer, as assessed by flow cytometry, immunoblotting, and susceptibility to complement-mediated lysis. By flow cytometry, CD55 and CD59 were present on RBC-derived microvesicles that stained with an antiglycophorin antibody Ab; in addition, soluble CD59 and CD55 were detected by immunoblot in soluble fractions eluated from RBC units stored for more than 35 days, but not in fresh blood. Both commercial HDL preparations and those prepared in our laboratory contained CD55 and CD59, as assayed by immunoblot. When RBC that were deficient (GPI)-anchored protein, obtained from five patients, with PNH were incubated with HDL preparations for 2 to 4 hours, there was significant transfer of both proteins to the cell surface, as demonstrated by flow cytometry. Washed RBC microvesicles, prepared by ultrasonification, also mediated transfer of GPI-linked proteins to deficient RBC. Pretreatment of microvesicles, RBC eluate preparations, and HDL with phosphatidylinositol-specific, phospholipase C, abrogated protein transfer to deficient cells, indicating that increased cell-associated CD55 and CD59 levels were related to insertion of the intact GPI moiety, rather than to simple adhesion. PNH RBC that were exposed to HDL, RBC eluate preparations, or microvesicles demonstrated decreased in vitro complement-mediated hemolysis in the Ham test. Transfer of GPI-linked proteins from soluble preparations containing CD55 and CD59 to PNH erythrocytes is feasible and may have clinical utility.

CD55 Antigens↗
PubMed1998

Overexpression of the fanconi anemia group C gene (FAC) protects hematopoietic progenitors from death induced by Fas-mediated apoptosis.

Fanconi anemia is a rare, inherited disorder characterized by bone marrow failure, congenital malformations, and cancer susceptibility. The group C Fanconi anemia gene, FAC, identified by expression cloning methods, encodes a protein of unknown function that may be involved in the response to apoptotic stimuli. Hematopoietic progenitor cells from Fac knock-out mice are hypersensitive to IFN-gamma, a molecule that can induce apoptosis through up-regulation of the Fas death receptor. In this study, we used FAC-overexpressing transgenic mice to examine the relationship between FAC and Fas-triggered cell death. Hematopoietic progenitors from FAC-transgenic mice were up to 10-fold less sensitive to the cytolytic effect of Fas-ligation. Our experiments implicate FAC in the regulation of apoptosis mediated by the Fas death receptor.

Animals↗
PubMed1998

Preoperative assessment criteria and patient teaching for ambulatory surgery patients.

Today's trend is to have the surgical patient return to the comfort of his or her home rather than be admitted to the hospital for expensive nursing and medical care. The perioperative team must initially assess the patient's American Society of Anesthesiology status, anxiety level, food and drugs to which he or she may be allergic, and skin integrity; obtain a medical and surgical history and consent; review laboratory, electrocardiogram, and radiological results; and perform preoperative teaching (e.g., which medications to take or withhold preoperatively, when to withhold food and fluids) and postoperative teaching (e.g., catheter care, dressing changes). In addition, the nurse needs to anticipate and be prepared for medical emergencies such as airway management problems and malignant hyperthermia. The age of the patient (e.g., pediatric and geriatric age groups) and preoperative disease states and their severity also need to be recognized as they impact on the perioperative outcome. The assessment phase is one of the most important phases in the perioperative experience. Proper evaluation is the key to success for positive surgical outcomes. Given the time constraints in the ambulatory surgical setting, assessing and teaching the patient on the day of surgery is not feasible or appropriate. Reaching out to the patient a few days before surgery either in the patient's home, in the ambulatory surgery center, or by telephone is the ultimate goal.

Adolescent↗
PubMed1998

Applications of Ion Microscopy and In Situ Electron Microscopy to the Study of Electronic Materials and Devices.

: We discuss the application of ion microscopy and in situ electron microscopy to the study of electronic and optical materials and devices. We demonstrate how the combination of in situ transmission electron microscopy and focused ion beam microscopy provides new avenues for the study for such structures, enabling extension of these techniques to the study of dopant distributions, nanoscale stresses, three-dimensional structural and chemical reconstruction, and real-time evolution of defect microstructure. We also discuss in situ applications of thermal, mechanical, electrical, and optical stresses during transmission electron microscopy imaging.

Journal Article↗
PubMed1998

Development of scales to measure psychosocial care needs of children with seizures and their parents. 1.

There is little research and no self-report assessment instruments available to guide nurses in the provision of psychosocial care to children with seizures and their families. Information on the development of two instruments, Report of Psychosocial Care Scale and Child Report of Psycyhosocial Care Scale, and their use in a research study to measure psychosocial care of children with new-onset seizures and their parents are presented in three parts. This first article describes development and initial testing of their psychometric properties. The second article, Part 2, "Psychosocial Care Needs of Parents of Children with New-Onset Seizures," describes results from the use of the parent scale with mothers and fathers of children with new-onset seizures. The third article, Part 3, "Psychosocial Care Needs of Children with New-Onset Seizures," reports findings from the use of the child scale with children ages 8-14 years with new-onset seizures.

Adaptation, Psychological↗
PubMed1998

Psychosocial care needs of children with new-onset seizures. 2.

The Child Report of Psychosocial Care Scale was used to measure children's satisfaction with health care received, need for information and support and seizure-related concerns and fears in children with new-onset seizures. The sample of 63 children (33 girls and 30 boys), 8-14 years, completed the scale two times, 3 months and 6 months after their first seizure. Results indicated that children need the most nursing care in two areas: information related to the seizure condition, especially managing their condition, and support, in the form of talking to other children with seizures. The scale provides direction for tailored nursing interventions that will meet the specific needs of children with seizures for information and support.

Adaptation, Psychological↗
PubMed1998

Psychosocial care needs of parents of children with new-onset seizures. 3.

The Parent Report of Psychosocial Care was developed to address the concerns, needs for care and satisfaction with care received of parents of children with new-onset seizures. Parents were interviewed three months and six months after their child's first seizures using the instrument. Mothers especially identified continued needs for information and support and were worried about unlikely events such as brain tumors and death. The results from this study indicate that parents' needs for information and support need to be assessed at every encounter with the health care system during the first 6 months after the child's first seizure.

Adaptation, Psychological↗
PubMed1997

Responsibilities of the preoperative holding area nurse.

The preoperative holding area is an important, but often over-looked, area in the surgical suite. This area, however, is where the majority of surgical patients and their family members have their first direct contact with perioperative staff members. The preoperative holding area can provide the environment for calming, informative interactions that should help patients prepare for their surgical procedures. The preoperative holding area nurse's primary responsibility is to provide information and emotional support for patients and their family members, to ensure that all preoperative data have been accumulated, and to maintain patients' baseline hemodynamic statuses.

Aged↗
PubMed1997

Malignant hyperthermia.

Malignant hyperthermia (MH) is a medical emergency that all perioperative nurses should be prepared to handle. Patients with the inherited MH trait have a rare skeletal muscle disease that causes them to develop life-threatening hyperthermia (ie, body temperatures of 43.3 degrees C [110.0 degrees F] or higher) at the time MH-triggering agents are administered to induce general anesthesia or shortly thereafter. The incidence of MH episodes is reported to be 1 in every 12,000 pediatric anesthetic procedures and 1 in every 40,000 adult anesthetic procedures. The MH syndrome also is characterized by continuous skeletal muscle rigidity, hypermetabolism, hypercapnia, tachypnea, and tachycardia that result in cardiac arrest and death if left untreated. Perioperative staff members' knowledge of MH, the care of MH-susceptible patients, and adequate preparation for MH crises are the cornerstones of successful patient outcomes to this life-threatening syndrome.

Adult↗
PubMed1997

Ciprofloxacin-resistant Escherichia coli emerging in a rehabilitation medical center.

A retrospective review of laboratory records from 1988 to 1996 has shown an increased rate of ciprofloxacin-resistant (cip(r)) Escherichia coli in our rehabilitation center. Resistance increased from 0.6% in 1989 to 5.9% in 1996. Of 7870 E. coli strains isolated during this period, 257 cip(r)-E. coli were recovered from 257 patients. The majority (96%) of these resistant strains were isolated from the urine samples. One hundred and twenty strains of cip(r)-E. coli were also resistant to four other fluoroquinolones. MICs ranging from 64 to 512 micrograms/mL were observed in 75% of the strains and > or = 1028 micrograms/mL in 6.4% of the strains. Resistance to ciprofloxacin was due to possible mutations in topoisomerase gyrA.

Anti-Infective Agents↗