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Biomedical subjects

S A Murray

Publications and source records attributed to S A Murray.

At least 19 recordsLinked to original sources
PubMed1997

Relationship of cytoskeletal filaments to annular gap junction expression in human adrenal cortical tumor cells in culture.

In addition to the well-characterized surface gap junctions expressed at contact sites between cells, annular gap junction profiles have been localized within the cytoplasm of some cell populations. To study and characterize these annular profiles, gap junction protein type was demonstrated with Western blot and immunocytochemistry. The distribution of annular gap junctions and the relationships to cytoskeletal elements were demonstrated with immunocytochemical, transmission electron microscopic, or image analysis with confocal microscopy techniques. SW-13 adrenal cortical tumor cells expressed alpha1 gap junctions at areas of cell to cell contact. In addition, alpha1 gap junction annular profiles were seen within the cytoplasm. Actin and myosin II were found closely associated with these annular gap junctions, while no physical association between tubulin- or vimentin-containing fibers and gap junction protein could be established. Disruption of microfilaments with cytochalasin B treatment (10 microg/ml, 1 h) resulted in a decrease in the average number and an increase in the average size of annular gap junctions compared to control populations. The results are consistent with a role for cytoskeletal elements containing actin and myosin II in annular gap junction turnover.

Actin Cytoskeleton↗
PubMed1997

Transcriptional and post-transcriptional control of lysyl oxidase expression in vascular smooth muscle cells: effects of TGF-beta 1 and serum deprivation.

Transforming growth factor-beta 1 (TGF-beta 1) markedly reduced cell proliferation and elevated steady state lysyl oxidase (LO) mRNA 3-fold in neonatal rat aorta smooth muscle cells cultured in medium containing 10% fetal bovine serum. The increase in LO mRNA was prevented by the presence of cycloheximide, indicative of controlling events at the level of protein synthesis. The basal level of mRNA in cells proliferating in 10% fetal bovine serum in the absence of TGF-beta 1 was enhanced 7-fold upon decreasing growth by shifting to medium containing 0.5% serum. Changes in LO activity paralleled those in LO mRNA. Nuclear run-on assays revealed that the stimulation of expression in 0.5% serum involved increased gene transcription whereas that caused by TGF-beta 1 was mostly post-transcriptional in origin. LO mRNA was quite labile (t1/2 approximately 3 h) in 10% serum but was markedly stabilized (t1/2 > 12 h) by the presence of TGF-beta 1 in the 10% serum medium. LO mRNA was also considerably more stable under retarded growth conditions (0.5% serum) in the absence of TGF-beta 1. LO promoter activity in luciferase reporter constructs transfected into these cells was low and not significantly affected by the addition of TGF-beta 1 to the 10% serum medium but was markedly elevated by shifting from 10 to 0.5% serum in the absence of TGF-beta 1. Thus, LO expression is inversely correlated with cell proliferation, and is subject to control at transcriptional and post-transcriptional levels. TGF-beta 1 enhances LO expression in these cells by dramatically stabilizing LO mRNA.

Animals↗
PubMed1997

Comparison of gap junction expression in the adrenal gland.

The presence of alpha 1 (Cx43) gap junction protein was demonstrated in rat, mouse, guinea pig, and bovine adrenal glands with immunocytochemical techniques. The presence of six other connexin species was not detected in the adrenal glands studied. The gap junction stain within the adrenal cortex was punctate and located at sites of cell-cell contact. While little gap junction, alpha 1, staining was detected at sites of cell contact in the zona glomerulosa (ZG), the zona fasciculata (ZF) and zona reticularis (ZR) had intense staining at cell contacts in all rodent species studies. In the bovine adrenal, ZG cells were connected by large gap junctions as were the cells of the ZF and ZR. The variations in alpha 1 distribution within the adrenal cortex may correspond with the different division rates and hormone functions within the adrenal gland as well as species differences between rodent and bovine adrenal gland.

Adrenal Glands↗
PubMed1997

The role of alpha1 (connexin-43) gap junction expression in adrenal cortical cell function.

To investigate the relationship between adrenal cell function and gap junction expression, a bovine adrenal cell line (SBAC) was studied. Western blot and immunocytochemical techniques were used to demonstrate gap junction expression in SBAC cell populations. Cells expressed alpha1 (connexin 43) gap junction protein at points of cell-to-cell contact. Gap junction number and size increased in populations treated with ACTH (40 mU/ml) or dibutyryl cAMP (DbcAMP, 1.0 mM). Treatment with either ACTH or DbcAMP increased steroid production and cAMP levels. SBAC cell number, however, decreased in ACTH- or DbcAMP-treated populations. The number of cells increased in cultures transfected with alpha1-antisense complementary DNA. Neither ACTH nor DbcAMP treatment decreased cell number or increased steroidogenesis in alpha1-antisense complementary DNA-transfected cell populations. However, cell populations in which gap junctions were inhibited retained the capacity to increase cAMP production in response to ACTH (40 mU/ml) treatment. Hormone-stimulated gapjunction expression and cell communication may represent an important factor in adrenal gland function and control of proliferation.

Adrenal Cortex↗
PubMed1996

The incidence and epidemiology of beta-lactam resistance in Haemophilus influenzae.

Consecutive isolates of Haemophilus influenzae were collected by the Public Health Laboratory, Bath between 1 June 1992 and 31 May 1993. Of 379 apparently distinct isolates, 216 originated from the respiratory tract, 102 from eyes and 61 from other sites. The minimum inhibitory concentrations of amoxycillin, amoxycillin/clavulanate, cefaclor, cefuroxime, cefotaxime and cefpodoxime were determined for each isolate. Forty strains (10.6%) were beta-lactamase producers. MIC50 and MIC90 values and the range of MICs were determined for all isolates. The overall resistance rates were: amoxycillin (MIC > 1.0 mg/L), 22.7%; amoxycillin/clavulanate (MIC > 1.0 mg/L), 14.8%; cefuroxime (MIC > 1.0 mg/L), 18.5%, (MIC > 4.0 mg/L), 5.5%; cefaclor (MIC > 8 mg/L), 15.6%; cefpodoxime (MIC > 1.0 mg/L), 0.3%; cefotaxime (MIC > 1.0 mg/L), 0%. Twenty non-beta-lactamase producing but beta-lactam resistant strains (cefuroxime MIC > 4.0 mg/L) were matched with 20 susceptible strains on the basis of patient age, sex, and specimen type. The strains were characterised by outer-membrane protein (OMP), random amplified polymorphic DNA (RAPD) and ribotyping patterns. Eleven of the 20 resistant strains were indistinguishable by the methods used, suggesting spread of a single beta-lactam resistant, non-beta-lactamase producing clone. The distribution of resistant strains within the local community was plotted geographically.

Adolescent↗
PubMed1996

Human performance and control of multiple systems.

Many systems involving multiple remote sensors or machines require a single operator to control more than one device simultaneously. Interface design issues for such systems can be formidable because the inherent complexity of multiple-platform control creates significant opportunities for operator confusion and overload. An exploratory study was conducted to examine some of these issues using a simulated industrial security task. The experiment manipulated the type of remote sensor (fixed-site or mobile), the number of displays that had to be monitored, and two types of event complexity (number of targets and redundancy of target images) using response time as the dependent measure. Results showed that significant performance penalties may be encountered in multiple-platform control and that these penalties accumulate at seemingly low levels of complexity.

Adult↗
PubMed1995

Practice based health needs assessment: use of four methods in a small neighbourhood.

OBJECTIVE: To explore the use of four methods to define health needs in a community, with a view to formulating guidelines for practice based assessment of health needs. DESIGN: Collection of data on health needs for a specific neighbourhood with four complementary methods: rapid participatory appraisal, postal survey, analysis of routinely available small area statistics, and collation of practice held information. SETTING: Council estate of 670 homes in Edinburgh. MAIN OUTCOME MEASURES: Description and comparison of health needs found by the different methods. RESULTS: Each method yielded particular insights into both health and health care needs. CONCLUSIONS: An extended primary care team with public health support can assess health and health care needs in a neighbourhood by means of a mixture of quantitative and qualitative methods. Different methods may be more suitable to assess different health needs or to explore potential service provision in the community or in primary or secondary care. A composite method may be most informative.

Chronic Disease↗
PubMed1994

Listening to local voices: adapting rapid appraisal to assess health and social needs in general practice.

OBJECTIVES: To explore the use of rapid appraisal in defining the health and social needs of a community and to formulate joint action plans between the residents and service providers. DESIGN: Collection of data by an extended primary care team from three sources: existing documents about the neighbourhood, interviews with a range of informants, and direct observations to build a profile of the community. SETTING: Council estate of 670 homes in Edinburgh. MAIN OUTCOME MEASURES: Perceived problems of the community and suggestions for change. RESULTS: The interviews and focus groups identified six priorities for change, many of which were not health related. These changes have been or are being implemented. CONCLUSIONS: An expanded primary care team can use rapid appraisal as a first step in identifying and meeting local health needs. It facilitates a multidisciplinary approach and complements quantitative methods of assessing need.

Community Participation↗
PubMed1994

Proficiency testing of factor VIII:C activity assays at the Canadian Red Cross Society National Reference Laboratory.

A national proficiency testing program has been established to monitor the accuracy and precision of factor VIII:C (FVIII:C) assays performed at the various Blood Services Centres of the Canadian Red Cross Society involved in the collection and processing of either donor blood designated for component production or plasma destined for fractionation. This paper describes the preparation, design, and results of the first four exercises involving 19 laboratories. The exercises were designed to allow the investigation of intralaboratory variability between replicate samples and precision of assays as well as the causes of interlaboratory variability. The implementation of this program has led to improved precision and interlaboratory agreement on FVIII:C assays. These improvements were achieved mainly as a result of a modification in the method for sample dilution, an increase in both replicate testing of the same sample and the number of sample dilutions, and a reduction in the number of reagent systems used by various centres.

Canada↗
PubMed1993

Regulation of the 12-O-tetradecanoyl-phorbol-13-acetate-induced inhibition of intercellular communication.

Effects of the tumor promoter 12-O-tetradecanoyl-phorbol-13-acetate (TPA) and protein kinase C (PKC) inhibitors on cell-cell communication were studied in a normal rat liver cell line, clone 9. Communication was observed and quantitated with microspectofluorometric and image analysis techniques following scrape-loading of the cells with lucifer yellow. Lucifer yellow migrated as far as ten cells away from the scraped edge in control populations. Two minute TPA (25-50 micrograms/ml) treatment inhibited dye movement such that the dye remained mainly in the cells at the cut edge. The TPA-induced inhibition of cell-cell communication could be partially blocked by 15 min treatment of the cell populations with the PKC inhibitors trifluoperazine (30 micrograms/ml), staurosporine (2 x 10(-8) or 2 x 10(-6) M), sangivamycin (15 or 200 microM), or a PKC inhibitor peptide (20 micrograms/ml) scraped in at the same time as lucifer yellow. Normal communication was observed in cultures treated only with PKC inhibitors. Lower concentrations of TPA (50 ng/ml-1 micrograms/ml) used for 2 min did not inhibit dye communication. Our results demonstrate the phorbol ester-induced interruption of cell-cell communication. The inhibition of PKC by inhibitors eliminates the effect of TPA on communication. Our data are consistent with a role of PKC in the control of junctional communication.

Alkaloids↗
PubMed1993

Nurses or doctors: patient choice in family planning.

For many years at one inner city practice, practice nurses trained in family planning and using an in-house protocol have been providing family planning advice and supplies to patients initially seen by the general practitioner. Two hundred consecutive patients attending the practice nurse or doctor for family planning supplies or advice were invited to complete a questionnaire to assess their preferred career and their overall satisfaction with the services. The patients' perceptions of whom they thought most appropriate to deal with their family planning requirements were explored. The patients who had seen the nurse rather than the doctor claimed to be more up to date with their cervical smear, to have had their blood pressure (BP) checked, and to be generally more satisfied with the consultation. Apart from the initial consultation for oral contraception most patients stated they would prefer to attend the nurse.

Adolescent↗
PubMed1992

A comparative study of imipenem versus piperacillin plus gentamicin in the initial management of febrile neutropenic patients with haematological malignancies.

Three-hundred and twelve episodes of fever in 234 neutropenic patients with haematological malignancies were treated empirically with either imipenem or a combination of piperacillin and gentamicin. There were no significant differences in the percentages of patients responding to therapy at either 72 h (59% and 56% of assessable episodes in the imipenem and combination groups respectively) or at the end of treatment (55% and 53% of assessable episodes in the imipenem and combination groups respectively). Patients in the piperacillin plus gentamicin group experienced significantly more renal tubular damage whereas those who received imipenem suffered more nausea or vomiting. We conclude that imipenem monotherapy represents an acceptable alternative to piperacillin plus gentamicin as empirical therapy of the febrile neutropenic patient.

Adolescent↗