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Biomedical subjects

C Bailey

Publications and source records attributed to C Bailey.

At least 55 records · Page 3Linked to original sources
PubMed1995

Molecular epidemiology of ceftazidime resistant Enterobacteriaceae from patients on a paediatric oncology ward.

Between the autumn of 1989 and January 1990, 21 of the 44 children on the paediatric oncology ward of St. James's University Hospital, Leeds, UK were infected or colonised with Enterobacteriaceae producing extended-spectrum beta-lactamases. This represents 48% of the patients on the ward. Only six patients (14%) had microbiologically proven septicaemia caused by such bacteria during this period. Eighty-one isolates of Enterobacteriaceae producing extended-spectrum beta-lactamases derived from blood culture (7 isolates from 6 patients) or faecal samples (74 isolates) were available for examination. These comprised 28 Escherichia coli, 28 Klebsiella oxytoca, 11 Klebsiella pneumoniae, 10 Citrobacter freundii, 3 Enterobacter spp. and 1 Serratia marcescens. Clinical isolates were resistant to penicillins and to ceftazidime. Strains isolated in this study also showed multiple resistance to a range of antimicrobial agents. Transfer to a nalidixic acid resistant laboratory strain of E. coli UB5201 was attempted, but transfer of the ceftazidime resistance determinant was only successful in 25 isolates (31%). Examination of plasmid DNA revealed sequences in each isolate that hybridised with the TEM beta-lactamase gene probe used on a variety of plasmids ranging in size from 2.5- > 150 kb, sometimes found on several replicons in a single isolate. The TEM gene probe also hybridised with chromosomal DNA in a large number of isolates. Nucleotide sequence analysis demonstrated the presence of three extended-spectrum beta-lactamases: TEM-10B produced by two isolates, TEM-12B produced by 37 isolates and TEM-26B produced by 40 isolates. In two cases, isolates produced two beta-lactamases, and it proved impossible to identify these enzymes unequivocally. The genes encoding TEM-10B and TEM-26B both differ from TEM-12B by single nucleotide substitutions. Analysis of the ribotype patterns derived from the clinical isolates provided evidence for cross-colonisation between patients, and this was confirmed by analysis of the plasmid profiles. Four years after discontinuing ceftazidime and other extended-spectrum cephalosporins on this ward, patients were still colonised with bacteria that produced extended-spectrum beta-lactamases.

Base Sequence↗
PubMed1995

Nursing as therapy in the management of breathlessness in lung cancer.

Breathlessness has been described as an unpleasant sensation, but if it encompasses suffering, as some argue, it is much more than this. Breathlessness is also a major issue for people with cancer. Much of the effort to manage breathlessness has thus far focused on the treatment of underlying causes or on pharmacological strategies. In this paper, broader rehabilitative goals of care and treatment for breathlessness in lung cancer are addressed. Breathing control techniques have been developed to help patients with non-malignant disease to avoid breathlessness at rest or on exertion. A study is described (Corner et al., 1995) which evaluated the effectiveness of breathing retraining and psychosocial support for breathlessness in lung cancer. Breathlessness can be a frightening and powerful experience. It can symbolize a threat to life itself. In these circumstances, the goal of therapy is to alleviate loss of function and to ease the psychological burden that so restricts the individual. An 'integrative' model of breathlessness is discussed, in which the emotional experience of breathlessness is considered inseparable from the sensory experience and the biological mechanisms. Evidence is presented from a small study of the experiences of nurses working in the experimental clinic for breathlessness which suggests that the emotional consequences of breathlessness have a profound influence on how it is managed in practice. Finally, it is argued that symptoms are sometimes generalized too much. Experience is particular, not universal, and an open, accepting and therapeutic approach to managing illness has to be involved with messy and sometimes frightening emotions.

Breathing Exercises↗
PubMed1994

Aortic valve replacement after a Bentall procedure.

Porcine valve failure after a Bentall procedure presents a particularly challenging situation for cardiothoracic surgeons. We describe a patient who was initially turned down for operative intervention because of the excessive operative risk involved, but who subsequently underwent successful valve replacement without removal of the aortic conduit.

Aorta↗
PubMed1994

The MAXM hematology autoanalyzer. An alternative?

The MAXM is a compact blood count and differential analyzer that appeals to both the space-limited, full-service laboratory and the large outpatient practice. The authors compared the performance of the Coulter MAXM to the larger Coulter STKS. Linearity and precision studies were comparable to the STKS. MAXM leukocyte differentials were closely correlated with STKS and manual readings, being excellent in the neutrophil, lymphocyte, and eosinophil categories but poorer on monocyte counts. Basophil counts did not correlate with STKS or manual counts. Analyzer suspect flagging was similar in both machines, with the MAXM exhibiting slightly reduced sensitivity and greater specificity. MAXM processing of a single sample requires twice the time. The MAXM functions well for a large office practice and as a backup for large medical laboratories but, because of its hands-on requirements and lack of speed, cannot replace the larger, more automated analyzers.

Autoanalysis↗
PubMed1994

Education for home-care providers.

Continuing education for home-care nurses is necessary because of the many different levels of educational preparation among nurses working in this practice setting and the lack of a structured orientation program at many agencies. Unique educational needs include the need to feel confident with physical assessment skills, nursing diagnosis, family dynamics, patient teaching, and counseling. Competence in the use of computers and documentation forms also is a necessity. The development of any educational program should include identification of the target audience, needs assessment, planning and design of the program, strategy for implementation, and an evaluation strategy.

Clinical Competence↗
PubMed1994

Phenotypic variability in X-linked ocular albinism: relationship to linkage genotypes.

One hundred nineteen individuals from 11 families with X-linked ocular albinism (OA1) were studied with respect to both their clinical phenotypes and their linkage genotypes. In a four-generation Australian family, two affected males and an obligatory carrier lacked cutaneous melanin macroglobules (MMGs); ocular features were identical to those of Nettleship-Falls OA1. Four other families had more unusual phenotypic features in addition to OA1. All OA1 families were genotyped at DXS16, DXS85, DXS143, STS, and DXS452 and for a CA-repeat polymorphism at the Kallmann syndrome locus (KAL). Separate two-point linkage analyses were performed for the following: group A, six families with biopsy-proved MMGs in at least one affected male; group B, four families whose biopsy status was not known; and group C, OA-9 only (16 samples), the family without MMGs. At the set of loci closest to OA1, there is no clear evidence in our data set for locus heterogeneity between groups A and C or among the four other families with complex phenotypes. Combined multipoint analysis (LINKMAP) in the 11 families and analysis of individual recombination events confirms that the major locus for OA1 resides within the DXS85-DXS143 interval. We suggest that more detailed clinical evaluations of OA1 individuals and families should be performed for future correlation with specific mutations in candidate OA1 genes.

Albinism, Ocular↗
PubMed1993

Bone lead content assessed by L-line x-ray fluorescence in lead-exposed and non-lead-exposed suburban populations in the United States.

Measurements of lead (Pb) in bone reflect cumulative Pb exposure, whereas blood Pb levels are indices of absorption during the previous 21-30 days. This study was undertaken to estimate bone Pb concentrations by L-line x-ray fluorescence (LXRF) in a United States suburban population which was exposed to unusually high levels of Pb in emissions from an adjacent factory during 1963-1981, compared with concentrations similarly estimated in a matched suburban community without unusual Pb exposure. The mean bone Pb value in 269 residents of the highly exposed suburb (15 ppm) was 3-fold greater than that of the reference suburb (5 ppm). LXRF estimates of bone Pb identified those individuals at risk for adverse effects of Pb, whereas blood Pb levels were uninformative. Average LXRF-estimated bone Pb concentrations in residents of the unusually exposed suburb approximated estimated values in workers at Pb-processing factories.

Adolescent↗
PubMed1993

Biotin uptake and transport across bovine brain microvessel endothelial cell monolayers.

Primary cultures of bovine brain microvessel endothelial cells (BMECs) were used to characterize blood-brain barrier (BBB) uptake and transport of biotin. Both the uptake and the transcellular transport of either radiolabeled or fluorescein-conjugated biotin by confluent monolayers of BMECs were measured. Biotin uptake (Km = 123 microM) and bidirectional transport across BMEC monolayers was a saturable process and could be competed for by unlabeled biotin, biocytin, and biotinmethyl ester. Pantothenic and nonanoic acid were found not to be effective competitors for either biotin uptake or transport. The metabolic inhibitor, 2-deoxyglucose, had only small effects on the saturable apical-to-basolateral transport and apical uptake of biotin by BMECs. In contrast, basolateral-to-apical transport of biotin was substantially attenuated by 2-deoxyglucose pretreatment. Results supported the existence of specific and saturable uptake and efflux carrier systems for biotin in BMEC monolayers. The function of these systems was dependent to some degree on the metabolic status of the BMECs. Our findings confirm the existence of a biotin uptake system at the BBB in vivo and provide the first indication of an efflux system for biotin in BMECs.

Animals↗
PubMed1992

Bone marrow transplantation for high-risk childhood lymphoblastic leukaemia in first remission: experience in MRC UKALL X.

Bone marrow transplantation (BMT) has been recommended for children with high-risk acute lymphoblastic leukaemia (ALL) in first remission. The recent MRC UKALL X trial was designed to facilitate a non-randomised comparison between BMT and chemotherapy in children deemed to be at high risk of treatment failure. 198 children aged 1-15 had a presenting leucocyte count of more than 100 x 10(9)/l. All received induction and early intensification therapy. Children with an HLA-compatible sibling donor were eligible for BMT in first remission. All other children received cranial irradiation at 24Gy, late intensification, and two years of continuous treatment. 183 children achieved a stable remission of whom 111 were HLA typed; these tended to be older and to have T-cell ALL. A donor was identified in 41 cases, of whom 34 proceeded to BMT at a median time of 17 weeks; there was no difference in distribution of age, sex, or leucocyte count between the groups receiving BMT and chemotherapy. Comparison of the 144 children who were in remission at 17 weeks and received chemotherapy with the 34 proceeding to BMT showed no significant difference in event-free survival at five years (69% for BMT and 52% for chemotherapy). There were significantly more treatment-related deaths in the marrow transplant group (6 vs 4) and more relapses in the chemotherapy group (59 vs 4). There was no significant difference in event-free survival between children who were HLA typed and had a donor and those without a donor, although there were fewer relapses among the former. BMT can be evaluated in the context of a multicentre trial for paediatric ALL but the number of children with donors is too small to make a significant impact on overall survival. However, marrow transplantation was associated with a much lower relapse rate than that with the UK ALL protocol, and with better definition of higher risk patients BMT may be of benefit in some children with high-risk ALL in first remission.

Adolescent↗
PubMed1992

Purification and identification of bovine liver gamma-carboxylase.

The microsomal gamma-carboxylase catalyzes modification of a limited set of glutamyl residues to gamma-carboxyglutamyl residues in a vitamin K-dependent reaction that also utilizes O2 and CO2. We report the purification to apparent homogeneity of the bovine liver microsomal carboxylase. Affinity chromatography exploiting the association of the carboxylase with prothrombin precursor and carboxylase binding to the propeptide sequence were combined with ion-exchange chromatography and fractionation using immobilized lectins. A 3.5 x 10(5)-fold purification was obtained, which is the highest purification, by a factor of 35, yet reported for this enzyme. A single 98-kDa protein is obtained from this isolation. Carboxylase activity is associated with this protein by two different criteria. Antibodies prepared against the carboxylase detected the 98-kDa protein when used in Western analysis. In addition, the single 98-kDa protein was shown to comigrate with activity when electrophoresed in a nondenaturing gel system. The availability of purified preparations of carboxylase will facilitate an increased understanding of the complex biochemical reaction carried out by this protein.

Animals↗
PubMed1992

Cation-dependent transition between the quadruplex and Watson-Crick hairpin forms of d(CGCG3GCG).

The DNA oligonucleotide d(CGCG3GCG) can form either a Watson-Crick (WC) hairpin or a parallel-stranded quadruplex structure containing six G-quartet base pair assemblies. The exchange between these forms and single strands can be monitored using circular dichroism (CD). NMR results verified the assignment of specific CD bands to quadruplex and hairpin species, respectively. Cations stabilize the quadruplex in the order K+ greater than Ca2+ greater than Na+ greater than Mg2+ greater than Li+ and K+ greater than Rb+ greater than Cs+, indicating that K+ has an optimum ionic radius for complex formation and that ionic charge affects the extent of ion-induced stabilization. The quadruplex is stable in the presence of 40 mM K+ at micromolar DNA concentration and can be kinetically trapped as a metastable form when prepared at millimolar DNA concentration and then diluted into buffer containing 40 mM Na+. The concentration of K+ required to reverse the equilibrium from the hairpin to the quadruplex decreases sharply with increased DNA concentration. The quadruplex has an unusual pKa of ca. 6.8, indicating that C.C+ base pairs are probably forming. This system provides insights into some of the detailed structural characteristics of a ["G4-DNA".ion] complex and an experimental model for the recently proposed "sodium-potassium conformational switch" [Sen, D., & Gilbert, W. (1988) Nature 334, 364-366; Sen, D., & Gilbert, W. (1990) Nature 344, 410-414]. These results may help to explain the lack of cytidine residues in G-rich telomeric DNAs and suggest that methylation of GC-rich duplex DNAs in "GpC islands" may induce quadruplex formation within heterochromatin domains, resulting in reversible chromosomal condensation.

Base Sequence↗
PubMed1992

Intrapartum fetal stimulation testing.

Intrapartum vibroacoustic stimulation testing (VAST) had a sensitivity of 100%, a specificity of 59.6% and a positive predictive value of 27.6% for the detection of fetal acidosis in this study of 60 cases. The use of VAST could significantly reduce the requirement for fetal capillary blood sampling. However, fetal scalp stimulation (FSS) was found to be an unreliable test to exclude fetal acidosis.

Acidosis↗
PubMed1992

Measurement of dopamine, HVA and HMMA in untimed urine samples: establishment of age-related reference data in children.

We describe assays for homovanillic acid, hydroxymethylmandelic acid and dopamine that have proven practical and reliable during 3 years of routine use. Homovanillic and hydroxymethylmandelic acids were measured as trimethyl silyl derivatives by capillary gas chromatography. Dilution of samples prior to extraction was found to be necessary to achieve consistent recoveries of these acidic metabolites. Dopamine was assayed by high pressure liquid chromatography with electrochemical detection using an optimized method of catecholamine isolation that involved both ion exchange and alumina extraction. Untimed urine samples were collected from 140 hospitalized children. Age related reference data for the excretion of all three metabolites are reported. We suggest certain precautions that should be observed when using untimed samples and relating the results to creatinine excretion.

Adolescent↗
PubMed1991

Comparison of the structure of the genes for outer membrane proteins P1 and P2 of Haemophilus influenzae type b.

Size and antigenic heterogeneity have been recognized in both outer membrane protein P1 and outer membrane protein P2 of Haemophilus influenzae type b. To determine the molecular basis for these differences, we have cloned and sequenced the structural genes for OMPs P1 and P2 from prototype isolates with the OMP subtypes 1H, 3L and 6U. The nucleotide and derived amino acid sequences of the P1 genes are characterized by three variable regions dispersed between highly conserved regions. The nucleic acid and derived amino acid sequences of the P2 genes are also highly conserved. The P2 genes from OMP subtype 1H and 3L isolates are identical. The sequence of the 6U gene differs by 13 nucleotides, resulting in 10 amino acid changes.

Bacterial Outer Membrane Proteins↗