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Biomedical subjects

A Adams

Publications and source records attributed to A Adams.

At least 19 recordsLinked to original sources
PubMed1992

Polyadenylic:polyuridylic acid-induced protection of BALB/c mice against acute murine cytomegalovirus infection.

Treatment of BALB/c mice with poly(A):poly(U) 18 h prior to infection with a lethal dose of murine cytomegalovirus (MCMV) increased survival. In parallel with increased survival, a 10- to 100-fold reduction of plaque-forming MCMV was found in the liver and spleen of mice 4 days post-infection with a sublethal dose of MCMV. Poly(A):poly(U) did not significantly increase natural killer cell activity or prolong the duration of elevated cytotoxic activity in infected animals. The possible role of interferon in the poly(A):poly(U)-induced protection of BALB/c mice is discussed.

Animals↗
PubMed1991

The value of drills in developing and maintaining numeracy skills in an undergraduate nursing programme.

The purpose of this study was to determine whether mathematical drills enhanced the ability of students of nursing to calculate drug dosages accurately. First year students were drilled and then tested over the next 2 years in drug calculations. It was found that repeated drilling improved students' ability to calculate drug doses but that this skill level diminished over time, in some instances to predrill levels of accuracy. An increase in the number of correct calculations was noticed in the two semesters in which students had a clinical placement leading the authors to conclude that, contrary to previous findings, work experiences do enhance the ability to calculate medication dosages. As safety and competency are essential in those areas of nursing practice which depend on mathematical ability, educational strategies which develop and retain mathematical skills are needed.

Drug Therapy↗
PubMed1990

Characterization of human fructose-1,6-bisphosphatase in control and deficient tissues.

The regulatory properties of human liver and muscle fructose-1,6-bisphosphatases (FBPase) have been studied in control tissues obtained at autopsy and in tissues from a neonate with FBPase deficiency who died as a result of an overwhelming acidosis. Evidence is presented which suggests that the alkaline isoenzyme of FBPase, which is widely regarded as a laboratory artefact, may have an important role in vivo in the regulation and control of glycolysis and gluconeogenesis. FBPase exhibits the hysteretic and dissociative properties associated with regulatory enzymes, and many of the factors which effect FBPase have inverse effects on phosphofructokinase activity, thus providing an integrated regulatory cycle for the control of the direction and rate of flux through the glycolytic pathway.

Catalysis↗
PubMed1990

Health promotion as a nursing function: perceptions held by university students of nursing.

Health care in Australia is more often perceived to be illness rather than health focused in nature. The increasing cost of health care has prompted a movement towards health promotion in the community demanding increasing involvement of health care professionals. This three year study was undertaken to determine the attitudes of students towards health promotion on entry and throughout a tertiary nursing programme. This longitudinal study was exploratory in nature and examined the attitudes of two student cohorts over the programme's three years. Entering students cited the health promotion function more frequently than did those nearing programme completion. There is a need to emphasise health promotion as a role if this is seen as desirable behaviour for comprehensively educated nurses. The perceptions of three intakes of students were examined. The function of health promotion was perceived to be important by entry students and was within the three most frequently mentioned functions.

Attitude of Health Personnel↗
PubMed1989

Replication of latent Epstein-Barr virus genomes in normal and malignant lymphoid cells.

DNA replication of 2 human lymphoid cell lines (U296 and Raji), latently infected with the Epstein-Barr virus, has been compared using a density transfer approach. Typical of non-malignant lymphoblastoid cells, U296 cells divided once in bromodeoxyuridine-supplemented medium to form hybrid but not heavy-density host DNA. Replication of the intracellular Epstein-Barr virus DNA was selectively inhibited in these cells with only 15% of the viral genomes duplicating once to form hybrid-density viral DNA. However, some heavy-density viral DNA was formed in the U296 cells and DNA synthesis can thus initiate again on newly duplicated viral genomes in cells that have traversed only a single S phase. These results contrast strongly with observations concerning the Burkitt-lymphoma-derived cell line. Lymphoma cells are not growth-inhibited and most of the latent Epstein-Barr virus genomes of the Raji line replicated once, and only once, in successive S phases. While the majority of the 50 Epstein-Barr virus genomes of both the Raji and U296 cell lines are maintained as extra-chromosomal DNA plasmids, the control of their duplication is distinctly different in the respective malignant and non-malignant host cells.

Antigens, Viral↗
PubMed1989

Severe acidosis in a neonate with pulmonary valve stenosis: a possible stress inducer of a fatal syndrome of fructose-1, 6-biphosphatase and aldolase deficiency.

A neonate is described whose clinical condition rapidly and irreversibly deteriorated on day two. He developed a profound acidosis, hypoglycaemia and a shock-like syndrome. The infant was centrally cyanosed and had a systolic murmur from a moderately severe pulmonary valve stenosis and a small atrial septal defect. The overwhelming acidosis was inconsistent with the severity of the congenital heart defects and as no infection was found a metabolic cause was sought. Liver tissue obtained at autopsy shortly after death on day four, showed deficiencies of fructose-1, 6-biphosphatase and aldolase.

Acidosis↗
PubMed1987

Replication of latent Epstein-Barr virus genomes in Raji cells.

The replication of the 50 to 60 latent, predominantly extrachromosomal, Epstein-Barr virus genomes maintained by the Burkitt-lymphoma-derived Raji cell line was investigated by using a Meselson-Stahl density transfer approach. Samples of DNA isolated from cells cultivated for different periods in bromodeoxyuridine-supplemented medium were fractionated according to density, and the distribution of viral and cellular DNAs among the heavy-, hybrid-, and light-density species was quantitated. The results indicate that the majority of latent Epstein-Barr virus DNA plasmids each replicate once during the cell cycle.

Bromodeoxyuridine↗
PubMed1986

Differences between central and peripheral rat alpha-adrenoceptors revealed using binuclear ligands.

We have used two homologous series of binuclear ligands, diacridines and diquinolines, and the radioligand receptor assay to compare the topology of alpha 1- and alpha 2-adrenoceptors in rat cerebral cortex and kidney membranes. While the chain length-dependence of affinity of the diacridines, as well as that of the diquinolines, for the alpha 1-adrenoceptors of these central and peripheral tissues are similar, we find marked differences in affinity profiles for interaction with central and peripheral alpha 2-adrenoceptors. In the context of our previously proposed model for the binding of diacridines and diquinolines to alpha-adrenoceptors the results suggest that the surface features of central and peripheral alpha 2-adrenoceptors differ in the area surrounding the noradrenaline binding site. This difference may prove to be of therapeutic relevance.

Acridines↗
PubMed1986

Effects of misoprostol on gastric acid and mucus secretion in man.

Misoprostol, a synthetic prostaglandin E1 analog, at doses of 200, 400, or 800 micrograms, and placebo were administered orally in random fashion to eight healthy male volunteers. The effects on basal and pentagastrin (0.6 microgram/kg/hr)-stimulated acid and mucus (N-acetylneuraminic acid measurement) secretion were then determined. Misoprostol in 200-, 400-, and 800-micrograms doses reduced basal acid secretion by 91%, 93%, and 93%, respectively. Mean 2-hr acid secretion was reduced by 27%, 33% (P less than 0.01), and 51% (P less than 0.01), respectively. Reductions in secretory volumes paralleled acid changes. Mucus secretion increased by 37%, 82%, and 95% during the basal period following misoprostol doses of 200, 400, and 800 micrograms, respectively. Increase in mucus of 27%, 31%, and 38% was observed during maximal acid inhibition (1-30 min) by misoprostol in 200-, 400-, and 800-micrograms doses. The concentration of gastric juice mucus was significantly increased. Subjects experienced no significant side effects during the study, and there were no significant changes in hematological or chemical blood studies. Misoprostol, a potent inhibitor of gastric acid secretion, also stimulates mucus secretion. This mucogenic effect may be important in the mucosal protective action of misoprostol and its antiulcer efficacy in man.

Adult↗
PubMed1985

Thermodynamics of agonist and antagonist binding to the alpha 1-adrenoceptor studied using [125I]BE 2254.

The thermodynamics of binding of [125I]BE 2254 to the alpha 1-adrenoceptor in guinea pig brain membranes have been investigated at four different temperatures between 0 and 37 degrees C. The affinity and binding capacity of the radioligand did not vary with temperature. Thus, the change in enthalpy upon binding was close to zero whereas the change in entropy was large and positive (delta S degrees approximately 45 cal/mol-deg). In addition, [125I]BE 2254 has been used as a reporter ligand to probe the thermodynamics of the interaction of a variety of alpha-adrenoceptor agonists and antagonists with the alpha 1-adrenoceptor. Binding of all ligands was associated with large positive changes in entropy (delta S degrees between 18 and 48 cal/mol-deg) and little, or no, change in enthalpy, a finding that provides no convincing evidence for conformational rearrangement of alpha 1-adrenoceptors upon ligand binding.

Animals↗
PubMed1985

Interaction of DNA-intercalating antitumor agents with adrenoceptors.

The interaction between some examples of mononuclear and binuclear DNA-intercalating antitumor agents and alpha- and beta-adrenoceptors has been studied using radioligand-binding assays. Competition for 125I-BE 2254, [3H]rauwolscine, and (-)-[3H]dihydroalprenolol binding was used to assess affinity for alpha 1-, alpha 2-, and beta-adrenoceptor-binding sites, respectively. Two homologous series of alkyl-linked diacridines and diquinolines were found to interact poorly with beta-adrenoceptors, with only the largest members having appreciable affinity. By contrast, these compounds bind strongly and in a complex manner to alpha 1- and alpha 2-adrenoceptors. The affinity of diacridines for both alpha-adrenoceptor classes has a parabolic dependence on alkyl chain length with the hexyl and pentyl derivatives being the most potent at the alpha 1- (Ki = 11.5 +/- 2.3 nM) and alpha 2- (Ki = 143 +/- 26 nM) binding sites, respectively. The dependence of inhibition constants on linker chain length for the diquinolines is more complicated, with the ethyl- and heptyl-linked dimers having the greatest affinity for each alpha subclass. There is a nadir in affinity for the pentyl and butyl ligands and an increase in dissociation constant for octyl and longer homologues. Thus, the ethyl diquinoline has Ki values of 6.6 +/- 1.2 and 110 +/- 14 nM for the alpha 1- and alpha 2- adrenoceptors, respectively, and, correspondingly, the heptyl derivative has values of 39 +/- 4 and 51 +/- 1 nM. These findings are discussed with respect to a model of the alpha-adrenoceptor in which the radioligand-binding site is situated in a trench or cleft, surrounded by a flat surface bounded by walls. Daunomycin was found to have no affinity for adrenoceptors of any type and mitoxantrone similarly fails to interact with alpha 2- and beta-adrenoceptors, but binds to the alpha 1 subclass with an inhibition constant (Ki) of 3930 +/- 420 nM. Bisantrene also has no affinity for beta-adrenoceptors but binds to alpha 1- and alpha 2- adrenoceptors with Ki values of 145 +/- 24 and 2310 +/- 430 nM, respectively. Among the mononuclear acridine drugs studied, only nitracrine shows detectable interaction with beta-adrenoceptors (Ki = 760 +/- 50 nM). This compound, like bisantrene, has high affinity for the alpha 1-adrenoceptor (Ki = 131 +/- 17 nM) and moderate affinity for the alpha 2 subclass (Ki = 2180 +/- 500 nM).(ABSTRACT TRUNCATED AT 400 WORDS)

Acridines↗
PubMed1979

The biochemical consequences of cardiopulmonary bypass surgery in children.

The changes in serum enzyme activities after successful and uncomplicated cardiopulmonary bypass (CPB) surgery in children are described. After maximum serum enzyme activities were attained, they thereafter declined steadily without any secondary peaks of activity, to be at or near normal activities by the seventh day after surgery. The possible sources and mechanisms of enzyme leakage from tissues after CPB are discussed. The concentration of some physiologically important constituents were determined in pump prime fluids and in the common circulation on bypass. The consequences of haemodilution on small children were undesirably reduced concentrations of magnesium, calcium and albumin, and this state persisted for some days after the end of bypass. Some possible implications of such unphysiological pump primes are discussed. We suggest that ASp AT, Ala AT, CK-MB, magnesium, calcium and urea should be routinely monitored for the first four days after surgery.

Alanine Transaminase↗
PubMed1979

Sites of sequence variability in Epstein-Barr virus DNA from different sources.

The intracellular Epstein-Barr virus (EBV) DNA present in virus-transformed cells was partly purified from 23 cell lines or biopsies of Burkitt lymphoma, nasopharyngeal carcinoma, infectious mononucleosis, or healthy carrier origin. Such DNA was cleaved in fragments (A-K) of molecular weights between 1 x 10(6) and 30 x 10(6) with restriction enzyme EcoRI, and these fragments were analyzed by standard methods involving agarose gel electrophoresis, transfer to nitrocellulose filters, and hybridization with radioactive EBV DNA or complementary RNA. Sequence variability among different EBV DNA isolates was largely confined to the A, C, and I fragments. These results are discussed in relation to the linkage map of the EcoRI fragments of EBV DNA. The EcoRI cleavage pattern of intracellular viral DNA of an EBV-like virus from baboon cells, Herpesvirus papio, was entirely different from that of human EBV isolates.

Animals↗
PubMed1979

Intracellular state of Epstein-Barr virus DNA in producer cell lines.

The physical state of the Epstein-Barr virus (EBV) DNA in three cell lines which spontaneously produce virus has been characterized. Circular EBV DNA molecules have been found in P3HR-I, B95-8 and M8I cells. The size of the intracellular M8I circular EBV DNA molecules is comparable with the linear virus genome isolated from virus particles but the circular P3HR-I and B95-8 DNA molecules are shorter than the virion DNA . In addition to the circular form, some EBV DNA with physical properties indicative of integrated sequences was found in all three producer cell lines. There was no marked change in the amount of either the circular or integrated forms of EBV DNA when these producer cell lines were grown in the presence of phosphonacetic acid to suppress the spontaneous virus production which occurs in a small percentage of the cells in untreated cultures.

Animals↗