PubMed Health⌕ Search

Biomedical subjects

C M O'Brien

Publications and source records attributed to C M O'Brien.

18 recordsLinked to original sources
PubMed2006

Consent for plastic surgical procedures.

The objective of this study was to examine patients' attitudes to providing consent for elective plastic and reconstructive surgical procedures and to identify their priorities in terms of information disclosure. Sixty-three consecutive patients attending the elective plastic and reconstructive surgery preadmission clinics at Sandwell Hospital, West Bromwich were prospectively audited by means of a questionnaire which included both open and closed questions. Seventy-five percent of patients volunteered that 'they ought' to have certain information disclosed prior to giving their consent to a surgical procedure. (It was interesting to note that the information they volunteered as wanting to know was not consistently the information that guidelines suggest they are told.) The provision of information is at the centre of the process of valid consent. This study shows the priorities of a group of elective patients prior to plastic surgery procedures, and highlights to clinicians the importance of tailoring information to individual patients.

Adult↗
PubMed2003

A comparison of cyclizine, ondansetron and placebo as prophylaxis against postoperative nausea and vomiting in children.

Nausea and vomiting is a relevant and common problem with unfavourable sequelae in children undergoing some plastic surgery procedures. There is a lack of anti-emetic trials performed in children, with only a few investigating the roles of the older anti-emetic agents such as cyclizine compared with newer ones such as ondansetron. This randomised, controlled, double-blind study examined the effectiveness of a single dose of ondansetron (0.1 mg x kg-1), cyclizine (20 mg) and placebo (normal saline) in the prevention of postoperative nausea and vomiting in 150 children (mean age 3.6 years) undergoing plastic genitourinary procedures. Rates of previous postoperative nausea and vomiting and motion sickness were comparable across the groups. Postoperative vomiting was significantly reduced with ondansetron prophylaxis (p = 0.006) but there was no detectable anti-emetic effect with cyclizine. Furthermore, cyclizine caused pain on injection (p < 0.001).

Analgesics, Opioid↗
PubMed2002

Sleep deprivation, disorganization and fragmentation during opiate withdrawal in newborns.

OBJECTIVE: To determine specific sleep characteristics in neonatal opiate withdrawal, referred to as the Neonatal Abstinence Syndrome (NAS), by measuring sleep efficiency, deprivation, disorganization and fragmentation in three groups: (i) healthy term neonates; (ii) opiate-exposed neonates who were treated for opiate withdrawal; and (iii) a group of opiate-exposed neonates who did not require treatment. METHODS: A cohort study recording sleep patterns of neonates at 2-10 days of age (after 36 or more weeks of gestation) was carried out. Twenty-one neonates were exposed to opiates during pregnancy and 15 neonates were healthy controls. Sleep characteristics were predefined, and treated newborns were divided into early and stabilized treatment groups. Polygraphic recordings of sleep, movement and breathing were made continuously after a daytime feed. RESULTS: Sleep deprivation, disorganization and fragmentation were found in newborns with NAS and were associated with the severity of the withdrawal. Neonates treated for NAS displayed increased wakefulness during early treatment (deprivation), but were similar to controls once stabilized. Both treated and non-treated groups had reduced amounts of quiet sleep (deprivation). Treated newborns showed an increase in indeterminate sleep (disorganization) and arousals-to-wakefulness (fragmentation). CONCLUSION: This study determined the exact nature and degree of sleep disturbances in newborns during acute opiate withdrawal. The findings contribute to a further understanding of the physiology underlying neonatal opiate withdrawal and suggest that some changes in sleep are due to opiate withdrawal but others may reflect opiate dependency in utero.

Electroencephalography↗
PubMed2000

Isolation of pluripotent embryonic stem cells from reprogrammed adult mouse somatic cell nuclei.

Pluripotent human stem cells isolated from early embryos represent a potentially unlimited source of many different cell types for cell-based gene and tissue therapies [1-3]. Nevertheless, if the full potential of cell lines derived from donor embryos is to be realised, the problem of donor-recipient tissue matching needs to be overcome. One approach, which avoids the problem of transplant rejection, would be to establish stem cell lines from the patient's own cells through therapeutic cloning [3,4]. Recent studies have shown that it is possible to transfer the nucleus from an adult somatic cell to an unfertilised oocyte that is devoid of maternal chromosomes, and achieve embryonic development under the control of the transferred nucleus [5-7]. Stem cells isolated from such a cloned embryo would be genetically identical to the patient and pose no risk of immune rejection. Here, we report the isolation of pluripotent murine stem cells from reprogrammed adult somatic cell nuclei. Embryos were generated by direct injection of mechanically isolated cumulus cell nuclei into mature oocytes. Embryonic stem (ES) cells isolated from cumulus-cell-derived blastocysts displayed the characteristic morphology and marker expression of conventional ES cells and underwent extensive differentiation into all three embryonic germ layers (endoderm, mesoderm and ectoderm) in tumours and in chimaeric foetuses and pups. The ES cells were also shown to differentiate readily into neurons and muscle in culture. This study shows that pluripotent stem cells can be derived from nuclei of terminally differentiated adult somatic cells and offers a model system for the development of therapies that rely on autologous, human pluripotent stem cells.

Animals↗
PubMed1997

Specificity for activase is changed by a Pro-89 to Arg substitution in the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase.

Tobacco activase does not markedly facilitate the activation of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco, EC 4.1.1. 39) from non-Solanaceae species, including the green alga Chlamydomonas reinhardtii. To examine the basis of this specificity, we focused on two exposed residues in the large subunit of Rubisco that are unique to the Solanaceae proteins. By employing in vitro mutagenesis and chloroplast transformation, P89R and K356Q substitutions were separately made in the Chlamydomonas enzyme to change these residues to those present in tobacco. Both mutants were indistinguishable from the wild type when grown with minimal medium in the light and contained wild-type levels of holoenzyme. Purified Rubisco was assessed for facilitated activation by spinach and tobacco activase. Both wild-type and K356Q Rubisco were similar in that spinach activase was much more effective than tobacco activase. In contrast, P89R Rubisco was not activated by spinach activase but was well activated by tobacco activase. Thus, the relative specificities of the spinach and tobacco activases for Chlamydomonas Rubisco were switched by changing a single residue at position 89. This result provides evidence for a site on the Rubisco holoenzyme that interacts directly with Rubisco activase.

Animals↗
PubMed1997

Comparison of exposure standards in the mammography x-ray region.

Direct comparisons of the National Institute of Standards and Technology's (NIST) Ritz 20 kV to 100 kV standard free-air ionization chamber and a portable variable-length free-air ionization chamber designed by the University of Wisconsin-Madison Accredited Dosimetry Calibration Laboratory (UW-ADCL) were made on NISTs low-energy tungsten x-ray range. As a result of this direct comparison, NIST has established a UW-ADCL designed chamber, the Attix chamber, as the national standard chamber for the mammography energy x-ray range. The Ritz standard chamber and the Attix standard chamber have been extensively compared using the new molybdenum and rhodium beam qualities. The results indicate that exposure measurements in the mammography energy x-ray region with the two free-air chambers can be made with a discrepancy of less than 0.35%.

Evaluation Studies as Topic↗
PubMed1996

Age-related changes of glycosidases in human retinal pigment epithelium.

This study was undertaken to determine whether there are age-related changes in the specific activities of several glycosidases in fresh retinal pigment epithelial cells (RPE) isolated from the posterior pole of human donor eyes. One hundred and twenty-one pairs of eyes from human donors, between the ages of 43 and 95 years, were obtained from the National Disease Research Interchange (NDRI, Philadelphia, PA) and the Cleveland Ohio Eye Bank within 18 to 24 h of death. None had histories of diabetes, hepatitis, HIV infection, intraocular surgery, or documented age-related macular degeneration, although several older donors with evidence of drusen were included in the study. RPE cells were isolated from the posterior third of the retina using the conventional rush method and homogenized with a glass, Broeck tissue grinder. All post-nuclear supernatants were analyzed for glycosidase activity; a smaller number of nuclear pellets were assayed to verify that the majority of the enzyme activity was associated with the post-nuclear sypernatants. Glycosidase activity was quantitated fluorometrically by measuring the enzymatic release of umbelliferone from synthetic substrate preparations, specific for each enzyme. Total protein was determined by a micro BCA protein assay. Regression analysis revealed statistically significant age-related decreases for the specific activities of alpha-mannosidase (p = 0.0001), beta-galactosidase (p = 0.0001), N-acetyl-beta-glucosaminidase (p = 0.0001), and N-acetyl beta galactosaminidase (p = 0.0001) in fresh human donor RPE cells taken from the region of the posterior third of the retina that included the macula. Mannose and N-acetyl-glucosamine are major carbohydrate monomers of the oligosaccaride chains of human rhodopsin, and a relatively high percentage of the oligosaccharide chains are galactosylated. Defects in their degradation may lead to the accumulation of undigested residual material in the RPE.

Acetylglucosaminidase↗
PubMed1994

Characterization of peptide binding to the murine MHC class I H-2Kk molecule. Sequencing of the bound peptides and direct binding of synthetic peptides to isolated class I molecules.

Peptides that are bound by the murine class I MHC molecule H-2Kk have been isolated and sequenced. The initial step in the fractionation was affinity column isolation of the peptide-class I complex from either RDM-4 or x5563 tumor cell lines. Acid denaturation of the complex followed by HPLC fractionation of the peptides allowed us to sequence individual peptides, as well as pools of peptides. To date, a total of 10 sequences have been characterized, and all were 8 mers. The sequences were variable except for glutamic acid in the second position (P2) and isoleucine in the eighth (P8), which were highly conserved. To further study peptide binding to H-2Kk, a competitive binding assay consisting of the immobilized histocompatibility protein and a biotinylated self-peptide for signal generation was developed. A complete set of single-alanine variants for this one self-peptide was tested in the assay, demonstrating that substitution at P2 and P8 markedly decreased the affinity for the class I molecule; alanine at position 3 had an intermediate effect on binding. A comparison of the identified self-peptides for binding to H-2Kk showed that they differed in affinity by more than one order of magnitude. Influenza virus nucleoprotein peptide, SDY EGR LI, associated with the plate-bound class I molecule, and the resulting MHC-peptide complex could trigger TNF release by influenza-primed CTLs. This result demonstrated the functional activity of the plate-bound H-2Kk-peptide complex.

Amino Acid Sequence↗
PubMed1994

Plasmodium falciparum infection of splenectomized and intact Guyanan Saimiri monkeys.

Spleen-intact and splenectomized Saimiri monkeys of Guyanan origin were examined for their potential suitability for Plasmodium falciparum protection studies. The animals could be readily infected with adapted strains of P. falciparum (Indochina 1/CDC and Uganda Palo Alto FUP strains), but spontaneously recovered without drug treatment and without development of severe clinical disease. In intact animals, peak parasitemia prior to recovery generally ranged from 0.1% to 10%, whereas in splenectomized animals the peak parasitemia was generally higher so that some animals were given drug treatment to assist in recovery from infection. In reinfection studies, previously infected spleen-intact monkeys demonstrated sterile immunity to the homologous parasite strain but not to a heterologous strain. However, in monkeys infected with the heterologous strain, the peak parasitemia was less than in the first infection and of shorter duration. Splenectomized animals did not demonstrate sterile immunity although the peak parasitemia achieved was less than in the previous infection of each of these monkeys. While the lack of major clinical disease indicated that these monkeys did not provide a good animal model for human malaria, the development of protective immunity was consistent with a useful role in evaluating candidate vaccine antigens.

Animals↗
PubMed1991

Failure of recombinant vaccinia viruses expressing Plasmodium falciparum antigens to protect Saimiri monkeys against malaria.

Saimiri sciurus monkeys were immunized at multiple sites with recombinant vaccinia viruses expressing Plasmodium falciparum antigen genes and boosted 4 weeks later. Control monkeys were immunized with a thymidine kinase-negative vaccinia virus mutant. Two weeks later, all of the monkeys were challenged by intravenous inoculation of P. falciparum (Indochina strain) parasites. A group of unimmunized monkeys was challenged in parallel. All of the monkeys that received vaccinia virus recombinants or the control virus produced good anti-vaccinia virus antibody responses. However, those that received a single construct containing ring-infected erythrocyte surface antigen (RESA) given at eight sites did not produce significant antibody to any of the three major RESA repeat epitopes after immunization but were primed for an enhanced antibody response after challenge infection with P. falciparum. Most of the monkeys produced detectable antibodies to the RESA epitopes after challenge infection. One group of monkeys was immunized with four constructs (expressing RESA, two merozoite surface antigens [MSA-1 and MSA-2], and a rhoptry protein [AMA-1]), each given at two sites. While these monkeys failed to produce significant antibody against MSA-2 or AMA-1 after immunization, they produced enhanced responses against these antigens after challenge infection. Immunization involved an allelic form of MSA-2 different from that present in the parasite challenge strain, so that the enhanced responses seen after challenge infection indicated the presence of T-cell epitopes common to both allelic forms. No groups of monkeys showed any evidence of protection against challenge, as determined by examination of the resulting parasitemias.

Animals↗