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Biomedical subjects

J Bentley

Publications and source records attributed to J Bentley.

At least 37 records · Page 2Linked to original sources
PubMed1996

Child-related services in general accident and emergency departments.

A survey undertaken by the British Paediatric Association (BPA) in 1985 highlighted deficits in the services and facilities provided by accident and emergency (A & E) departments for children. Following this survey several documents were published by professional and voluntary organizations advising on the care of children in such departments. The current study, conducted as part of a larger project, involved the distribution of questionnaires (by post) to the nursing managers of a total of 193 general A & E departments in England, Scotland and Wales. The overall response rate of 87% was very encouraging. This article explores the nurse managers' perceptions of the personnel required to meet the needs of children in A & E. It looks especially at the role of Registered Sick Children's Nurses (RSCNs). The findings suggest that the need for RSCNs is not always accepted. RSCNs seem to be employed in some departments as a token presence. Factors seen by nurse managers as limiting their recruitment are discussed. According to the responses given, the role of the RSCNs currently employed in A & E, varies considerably. The findings give some insight into the degree to which current staffing for children in A & E meet the guidelines published by professional and voluntary bodies.

Accidents↗
PubMed1996

2-deoxy-D-glucose toxicity and transport in human multidrug-resistant KB carcinoma cell lines.

It is shown that a series of colchicine-selected multidrug-resistant (MDR) human KB carcinoma cell lines displayed increasing 2-deoxy-D-glucose collateral sensitivity, which correlated with increasing multidrug resistance. The relative resistance of MDR cell lines to 2-deoxy-D-glucose was reduced to 0.73 (KB-8-5), 0.3 (KB-8-5-11) and 0.2 (KB-C1) when compared with parental KB-3-1 (1.0). 2-Deoxy-D-glucose accumulation was found to be reduced in the MDR cell lines in a manner that correlated with 2-deoxy-D-glucose collateral sensitivity. At 30 min 2-deoxy-D-glucose accumulation was reduced to 0.61 (KB-8-5), 0.41 (KB-8-5-11) and 0.22 (KB-C1) relative to KB-3-1 uptake (1.0). The efflux of 2-deoxy-D-glucose was not significantly different between resistant and sensitive cell lines. Analysis of 2-deoxy-D-glucose uptake kinetics, by initial rate measurements, showed alterations in K(t) and J(max) for MDR when compared with KB-3-l cells. The levels of GLUT-1 facilitative transporter were found to be reduced significantly in the MDR cell lines in total cell homogenate and plasma membrane fractions by using Western blot analysis. Changes in the plasma membrane level of GLUT-1 correlated with 2-deoxy-D-glucose toxicity and uptake for MDR cell lines, where relative GLUT-i levels were reduced to 0.71 (KB-8-5), 0.43 (KB-8-5-1 1) and 0.27 (KB-Cl) relative to KB-31(1.0). It is concluded that the response of human KB MDR cells to 2-deoxy-D-glucose involved alterations in the level and activity of the facilitative glucose transporter, GLUT-1, in a manner that is associated with the degree of multidrug resistance.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

Voices of reform. The AHA: policy, advocacy and the tools for reform.

In three thoughtful essays, with an introduction by president Dick Davidson, executives at the AHA discuss the policy and political aspects of the reform process, and the organization's reform vision, including the development of tools for its membership.

American Hospital Association↗
PubMed1994

Large-scale production and characterization of recombinant human immunodeficiency virus type 1 Nef.

Sequences encoding the 27K and 25K nef gene products (Nef 27 and Nef 25) were amplified by PCR from a human immunodeficiency virus type 1 infectious clone and subcloned directly into Escherichia coli, yeast and baculovirus expression vectors. The yeast- and baculovirus-derived Nef had native N termini but the expression levels were low. The expression levels of the E. coli-derived glutathione S-transferase-Nef fusion proteins were very high and a major portion was soluble. Large-scale production of E. coli-derived Nef 27 and Nef 25 was carried out by growing recombinant cells in a fermenter under fed-batch conditions followed by affinity purification on glutathione-Sepharose before and after thrombin cleavage. Large quantities of highly purified recombinant Nef proteins have been produced for functional and structural studies. Under non-reducing conditions both Nef 27 and Nef 25 existed as a mixture of monomers, dimers and small amounts of higher oligomers, but when reduced were monomeric. The highly purified Nef proteins had no G protein activities, however Nef 27 was biologically active. When electroporated into uninfected CD4+ T lymphocytes both E. coli-derived Nef 27 and yeast-derived myristylated Nef 27 down-regulated the surface expression of CD4, demonstrating that this method can be used to assess the biological activity of purified recombinant Nef.

Base Sequence↗
PubMed1994

Expression of N-CAM in fertilized pre- and periimplantation and parthenogenetically activated mouse embryos.

The expression of the cell adhesion molecule of the immunoglobulin family, neural cell adhesion molecule (N-CAM), in the pre- and periimplantation embryo was examined by immunocytochemistry. N-CAM is expressed on unfertilized ovulated oocytes, fertilized preimplantation embryos at all stages of development and parthenogenetically activated eggs and embryos. In fertilized embryos, expression from the 4-cell stage can be partially inhibited by blocking embryonic transcription before 38 h post human chorionic gonadotropin (hCG). Expression of N-CAM was reduced on the trophoblast of day 6 blastocysts in culture, weak on the trophoblast of embryonic outgrowths and disappears from invading trophoblast in utero. An antibody against alpha(2-8) linked polysialic acid, mAb2-2B, reacted with embryos from the 8-cell stage, and staining was similarly reduced on the trophoblast of blastocysts at the time of implantation. These results suggest a role for N-CAM in the interactions of cells of the preimplantation mammalian embryo which requires further investigation.

Amanitins↗
PubMed1993

Cloning and sequence analysis of an Escherichia coli gene conferring bicyclomycin resistance.

We have cloned and sequenced DNA from Escherichia coli that, when present in a high-copy-number plasmid, confers resistance to the diketopiperazine antibiotic, bicyclomycin (Bc). The DNA includes a 378-amino-acid open reading frame (ORF), disruption of which results in the loss of Bc resistance. This ORF contains the BcR gene. Studies using the minicell expression system reveal that a polypeptide of 31 kDa is produced from this cloned region. The ORF maps at 47.1 min on the E. coli genome map. Sequence comparison between the translated ORF and a protein database reveal between 26.5 and 23.4% aa sequence homology to bacterial transmembrane (TM) proteins including those mediating chloramphenicol (Cm) and tetracycline (Tc) resistance and an arabinose-proton symport protein. Sequence analysis using the Diagon program showed the BcR gene product (BcR) had homology with the N-terminal regions of the CmR and TcR-encoded proteins and weak N-terminal homology with the arabinose-proton symport protein. Hydropathy profiles of the BcR protein and CmR products show a striking similarity, both having twelve predicted TM domains.

Amino Acid Sequence↗
PubMed1993

A preliminary report of vitamin D and calcium metabolism in older African Americans.

OBJECTIVE: To determine normal serum bone-related biochemical variables in older African-Americans. DESIGN: A convenience sample of older African-Americans who had a health screening and blood testing for calciotropic hormones was compared with white Americans who were recruited at the end of the Systolic Hypertension in the Elderly Program (SHEP) study and were not on a thiazide diuretic. SETTING: Community-dwelling African-Americans who participated in SHEP or who attended one of two mass health screenings. PARTICIPANTS: Thirty-two African-Americans aged 68-93 years and 43 white Americans aged 70-89 years. MEASUREMENTS: Twenty-five hydroxyvitamin D (25OHD), parathyroid hormone, osteocalcin, and calcitonin. RESULTS: Serum 25OHD levels in 38% of the African-American men and 38% of African-American women were less than 8 ng/mL compared with 22% of Caucasian men and 40% of Caucasian women. Serum parathyroid hormone (PTH) was above the normal range in 25% of men and 33% of women of African-American descent and 14% of Caucasian men and 30% of Caucasian women. Serum 25OHD was lower (P < 0.05) in individuals with a previous history of fracture. Serum albumin (P < 0.05), calcitonin (P < 0.05), and osteocalcin (P < 0.05), but not 25OHD, were lower in African-Americans (men and women) when compared with Caucasians (P < 0.05). Serum calcium corrected for albumin was higher in the African-Americans than in the Caucasians (P < 0.05). As previously reported in Caucasians, PTH was inversely related to log 25OHD in African-Americans. Serum osteocalcin was positively correlated to PTH in African-Americans, as previously reported in Caucasians. Log 25OHD correlated inversely with osteocalcin in African-Americans, but this was not seen in Caucasians. CONCLUSIONS: In this limited sample, hypovitaminosis D (as assessed by 25OHD level) with secondary hyperparathyroidism occurred frequently in elderly African-Americans. Osteocalcin, a measure of osteoblast activity, correlated with 25OHD and parathyroid hormone. Osteocalcin serum levels were lower in African-Americans than Caucasians, but serum calcium corrected for albumin was higher in the former compared to the latter.

Aged↗
PubMed1992

Granulocyte colony-stimulating factor to prevent dose-limiting neutropenia in non-Hodgkin's lymphoma: a randomized controlled trial.

The effect of granulocyte colony-stimulating factor (G-CSF) on neutropenia, infection, and cytotoxic chemotherapy administration was studied in a randomized trial in patients receiving intensive weekly chemotherapy for non-Hodgkin's lymphoma (NHL). Eighty patients (aged 16 to 71 years) with high-grade NHL (Kiel) of any stage were randomized to receive VAPEC-B chemotherapy alone (39 patients) or with G-CSF administered as a daily subcutaneous dose of 230 micrograms/m2 (41 patients). Prophylactic ketoconazole and cotrimoxazole were administered to all patients throughout treatment. The protocol specified identical dose modification and antibiotic treatment criteria bor both groups. Neutropenia (absolute neutrophil count [ANC] less than 1.0 x 10(9)/L) occurred in 15 of 41 (37%) of the G-CSF-treated patients and in 33 of 39 (85%) of the controls, giving a relative risk for control patients of 2.31 (95% confidence interval [CI], [1.51, 3.54]; P = .00001). Fever (greater than or equal to 37.5 degrees C) with neutropenia (ANC less than 1.0 x 10(9)/L) occurred in 9 of 41 (22%) of the G-CSF group and in 17 of 39 (44%) of the controls (relative risk for control, 2.26; 95% CI [1.01, 5.06]; P = .04). There were fewer treatment delays, with shorter duration (P = .01) in patients receiving G-CSF. Chemotherapy doses were reduced in 4 of 41 (10%) of the G-CSF patients and 13 of 39 (33%) of the controls (P = .01). The dose intensity of cytotoxic chemotherapy was significantly increased in patients receiving G-CSF (median of 95% in G-CSF group compared with 83% in control patients). Three vascular deaths occurred in the G-CSF group. Delays in the control group most commonly resulted from neutropenia (19 patients, compared with 2 patients in the G-CSF-treated group, P = .000007). Severe mucositis was the major dose-limiting toxicity in G-CSF-treated patients, but did not occur more frequently than in controls (15 patients in each group). Overall, patients randomized to receive G-CSF achieved a greater dose intensity than control patients, but this did not result in significant differences in drug toxicity (other than neutropenia), intravenous antibiotic usage, or hospitalization between the two groups.

Adolescent↗
PubMed1992

Reflection electron energy-loss spectroscopy and imaging for surface studies in transmission electron microscopes.

A review is given on the techniques and applications of high-energy reflection electron energy-loss spectroscopy (REELS) and reflection electron microscopy (REM) for surface studies in scanning transmission electron microscopes (STEM) and conventional transmission electron microscopes (TEM). A diffraction method is introduced to identify a surface orientation in the geometry of REM. The surface dielectric response theory is presented and applied for studying alpha-alumina surfaces. Domains of the alpha-alumina (012) surface initially terminated with oxygen can be reduced by an intense electron beam to produce Al metal; the resistance to beam damage of surface domains initially terminated with Al+3 ions is attributed to the screening effect of adsorbed oxygen. Surface energy-loss near-edge structure (ELNES), extended energy-loss fine structure (EXELFS), and microanalysis using REELS are illustrated based on the studies of TiO2 and MgO. Effects of surface resonances (or channeling) on the REELS signal-to-background ratio are described. The REELS detection of a monolayer of oxygen adsorption on diamond (111) surfaces is reported. It is shown that phase contrast REM image content can be significantly increased with the use of a field emission gun (FEG). Phase contrast effects close to the core of a screw dislocation are discussed and the associated Fresnel fringes around a surface step are observed. Finally, an in situ REM experiment is described for studying atomic desorption and diffusion processes on alpha-alumina surfaces at temperatures of 1,300-1,400 degrees C.

Aluminum Oxide↗
PubMed1992

A pharmacokinetic and tolerance study of romazarit in patients with rheumatoid arthritis.

Romazarit is a new drug for which animal pharmacology suggests a disease-modifying action in rheumatoid arthritis (RA). These animal studies predict that plasma romazarit concentrations within the range 50-100 mg l-1 may be required for efficacy in the clinic. Therefore, a pharmacokinetic study was designed to estimate the dosage required to achieve these concentrations in man. Twenty-four patients with RA entered a double-blind controlled assessment receiving either placebo, 100 mg t.i.d., 350 mg b.i.d., or 350 mg t.i.d., for 6 days. Pharmacokinetic profiles were measured after single doses and after the last of the multiple doses. Adverse events were mainly trival and were distributed almost equally between all three treatment and the placebo groups. Plasma romazarit concentrations were not dose-proportional after the single doses. Mean peak plasma drug concentrations were 11.8, 66.7, and 159 mg l-1 at steady state after 100 mg t.i.d., 350 mg b.i.d., and 350 mg t.i.d. The mean urinary recovery of drug-related material (mostly ester glucuronides) was 71 per cent of the dose during the dosage interval. The renal clearance of romazarit glucuronides correlated with creatinine clearance (p less than 0.01). Saturable tubular secretion of glucuronides coupled with reversible glucuronidation would explain these findings. It is predicted that oral doses of 450 mg romazarit given 12-hourly will result in plasma concentrations within the target range of 50-100 mg l-1.

Administration, Oral↗
PubMed1991

Introducing confident midwives: Midwifery Education--Action for Safe Motherhood.

The present crisis in midwifery and the seriousness of maternal mortality and morbidity demands a rethink about the background and training requirements of each level of midwifery worker. This paper describes the background of the present shortage and mal-distribution of midwives. The reduction of maternal mortality by 50% at the turn of this century requires the development of a maternal health care team in which the midwife functions as the linchpin. In order to equip the midwife for the leadership functions in this team, the present educational system needs to be fundamentally improved. The rationale for the acquisition of epidemiological, managerial specialised technical and teaching skills by midwives is discussed. Implications for further education are high-lighted. Collaborative actions taken by the WHO, ICM, UNICEF and other governmental and non-governmental agencies to address the issue of midwifery are outlined. This paper was given at the 1990 ICM, WHO, UNICEF Pre-Congress Workshop on Midwifery Education--Action for Safe Motherhood in Kobe, Japan.

Clinical Competence↗