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Biomedical subjects

M Murphy

Publications and source records attributed to M Murphy.

At least 19 recordsLinked to original sources
PubMed2001

ATM phosphorylates histone H2AX in response to DNA double-strand breaks.

A very early step in the response of mammalian cells to DNA double-strand breaks is the phosphorylation of histone H2AX at serine 139 at the sites of DNA damage. Although the phosphatidylinositol 3-kinases, DNA-PK (DNA-dependent protein kinase), ATM (ataxia telangiectasia mutated), and ATR (ATM and Rad3-related), have all been implicated in H2AX phosphorylation, the specific kinase involved has not yet been identified. To definitively identify the specific kinase(s) that phosphorylates H2AX in vivo, we have utilized DNA-PKcs-/- and Atm-/- cell lines and mouse embryonic fibroblasts. We find that H2AX phosphorylation and nuclear focus formation are normal in DNA-PKcs-/- cells and severely compromised in Atm-/- cells. We also find that ATM can phosphorylate H2AX in vitro and that ectopic expression of ATM in Atm-/- fibroblasts restores H2AX phosphorylation in vivo. The minimal H2AX phosphorylation in Atm-/- fibroblasts can be abolished by low concentrations of wortmannin suggesting that DNA-PK, rather than ATR, is responsible for low levels of H2AX phosphorylation in the absence of ATM. Our results clearly establish ATM as the major kinase involved in the phosphorylation of H2AX and suggest that ATM is one of the earliest kinases to be activated in the cellular response to double-strand breaks.

Androstadienes↗
PubMed2001

Development and reorganization of corticospinal projections in EphA4 deficient mice.

The Eph family of receptor tyrosine kinases and their ligands, the ephrins, are important regulators of axon guidance and cell migration in the developing nervous system. Inactivation of the EphA4 gene results in axon guidance defects of the corticospinal tract, a major descending motor pathway that originates in the cortex and terminates at all levels of the spinal cord. In this investigation, we report that although the initial development of the corticospinal projection is normal through the cortex, internal capsule, cerebral peduncle, and medulla in the brain of EphA4 deficient animals, corticospinal axons exhibit gross abnormalities when they enter the gray matter of the spinal cord. Notably, many corticospinal axons fail to remain confined to one side of the spinal cord during development and instead, aberrantly project across the midline, terminating ipsilateral to their cells of origin. Given the possible repulsive interactions between EphA4 and one of its ligands, ephrinB3, this defect could be consistent with a loss of responsiveness by corticospinal axons to ephrinB3 that is expressed at the spinal cord midline. Furthermore, we show that EphA4 deficient animals exhibit ventral displacement of the mature corticospinal termination pattern, suggesting that developing corticospinal axons, which may also express ephrinB3, fail to be repelled from areas of high EphA4 expression in the intermediate zone of the normal spinal cord. Taken together, these results suggest that the dual expression of EphA4 on corticospinal axons and also within the surrounding gray matter is very important for the correct development and termination of the corticospinal projection within the spinal cord.

Age Factors↗
PubMed2001

Dishevelled regulates the metabolism of amyloid precursor protein via protein kinase C/mitogen-activated protein kinase and c-Jun terminal kinase.

Alzheimer's disease (AD) is a disorder of two pathologies: amyloid plaques, the core of which is a peptide derived from the amyloid precursor protein (APP), and neurofibrillary tangles composed of highly phosphorylated tau. Protein kinase C (PKC) is known to increase non-amyloidogenic alpha-secretase cleavage of APP, producing secreted APP (sAPPalpha), and glycogen synthase kinase (GSK)-3beta is known to increase tau phosphorylation. Both PKC and GSK-3beta are components of the wnt signaling cascade. Here we demonstrate that overexpression of another member of this pathway, dishevelled (dvl-1), increases sAPPalpha production. The dishevelled action on APP is mediated via both c-jun terminal kinase (JNK) and protein kinase C (PKC)/mitogen-activated protein (MAP) kinase but not via p38 MAP kinase. These data position dvl-1 upstream of both PKC and JNK, thereby explaining the previously observed dual signaling action of dvl-1. Furthermore, we show that human dvl-1 and wnt-1 also reduce the phosphorylation of tau by GSK-3beta. Therefore, both APP metabolism and tau phosphorylation are potentially linked through wnt signaling.

Adaptor Proteins, Signal Transducing↗
PubMed2001

Common hereditary cancers and implications for primary care.

The identification of genes that place individuals at high risk of breast, ovarian, and colorectal cancer has greatly advanced our understanding of cancer predisposition over the past decade. This knowledge has received much attention from the media, and referrals to geneticists and surgeons, and requests for genetic testing, have risen. We review the published evidence for the management of people at increased risk of hereditary cancers, to draw attention to areas of uncertainty and to discuss implications for primary care. We focus on common inherited cancers, since they will have the greatest effect on clinical practice over the next decade. Cancer genetics offers a model of how information on the genetics of other common diseases could affect primary care in the future. Strategies to support the integration of genetic medicine in primary care are needed to enable primary-care practitioners to identify individuals at raised genetic risk and to reassure patients for whom genetic testing and increased surveillance offer little benefit.

Female↗
PubMed2001

Bromelain activates murine macrophages and natural killer cells in vitro.

The innate immune response is critical for effective immunity against most pathogens. In this study, we show that bromelain, a mixture of cysteine proteases, can enhance IFN-gamma-mediated nitric oxide and TNFalpha production by macrophages. Bromelain's effect was independent of endotoxin receptor activation and was not caused by direct modulation of IFN-gamma receptors. Instead, bromelain either enhanced or acted synergistically with IFN-gamma receptor-mediated signals. These effects were seen in both RAW 264.7, a macrophage cell line, and primary macrophage populations. Bromelain also increased IL-2- and IL-12-mediated IFN-gamma production by NK cells. These results indicate a potential role for bromelain in the activation of inflammatory responses in situations where they may be deficient, such as may occur in immunocompromised individuals.

Animals↗
PubMed2001

Self-replicative RNA vaccines elicit protection against influenza A virus, respiratory syncytial virus, and a tickborne encephalitis virus.

In genetic vaccination, recipients are immunized with antigen-encoding nucleic acid, usually DNA. This study addressed the possibility of using the recombinant alpha virus RNA molecule, which replicates in the cytoplasm of transfected cells, as a novel approach for genetic vaccination. Mice were immunized with recombinant Semliki Forest virus RNA-encoding envelope proteins from one of 3 viruses: influenza A virus, a tickborne flavivirus (louping ill virus), or respiratory syncytial virus (RSV). Serologic analyses showed that antigen-specific antibody responses were elicited. IgG isotyping indicated that predominantly Th1 type immune responses were induced after immunization with RSV F protein-encoding RNA, which is relevant for protection against RSV infection. Challenge infection showed that RNA immunization had elicited significant levels of protection against the 3 model virus diseases.

Animals↗
PubMed2001

Comparison of elderly people's technique in using two dry powder inhalers to deliver zanamivir: randomised controlled trial.

OBJECTIVE: To determine whether elderly people can learn to use the inhaler used to deliver zanamivir (Relenza Diskhaler) as effectively as the Turbohaler and to identify which aspects of inhaler technique are most problematic. DESIGN: Randomised, controlled, intervention study. SETTING: Wards for acute elderly care in a large district general hospital. PARTICIPANTS: 73 patients who were unfamiliar with the use of an inhaler, aged 71 to 99 (mean 83) years. MAIN OUTCOME MEASURES: Initial scores and changes in scores 24 hours later using a 10 point scoring system of five aspects of inhaler technique. RESULTS: 38 patients were allocated the Relenza Diskhaler and 35 the Turbohaler. The mean total score was significantly greater in the Turbohaler than Diskhaler groups both initially (8.74 v 7.05) and after 24 hours (8.28 v 5.43). The major difference between inhalers was in loading and priming. After tuition 50% (19 of 38) of patients allocated the Diskhaler were unable to load and prime the device and 65% (24 of 37) were unable to do so 24 hours later. Of those allocated the Turbohaler, two patients were unable to load and prime the device after initial review and one after 24 hours. CONCLUSION: Most elderly people cannot use the inhaler device used to deliver the anti-influenza drug zanamivir. Treatment with this drug is unlikely to be effective in elderly people unless the delivery system is improved.

Administration, Inhalation↗
PubMed2001

ELISPOT analysis of hepatitis C virus protein-specific IFN-gamma-producing peripheral blood lymphocytes in infected humans with and without cirrhosis.

An improved ability to monitor hepatitis C virus (HCV)-specific T cell immunity in infected patients may provide novel information regarding the pathogenesis and prognosis of this infection. We used an ELISPOT assay to analyze a cross-section of HCV-infected humans. HCV-infected patients without cirrhosis, those with cirrhosis, and controls with other liver diseases were tested for recall responses to HCV Core and NS3 proteins. Peripheral blood lymphocytes (PBLs) from HCV-infected patients without cirrhosis responded to NS3 and Core proteins, producing predominantly IFN-gamma, with little IL-4 or IL-5. In contrast, PBLs from HCV-infected patients with cirrhosis responded to NS3, but not to the Core protein, suggesting a selectively altered immune state during cirrhosis. Our data provide support for the notion that HCV-specific IFN-gamma-producing immunity is important in the pathogenesis of progressing HCV-related disease.

Enzyme-Linked Immunosorbent Assay↗
PubMed2001

An MRP system for surgical linen management at a large hospital.

Materials Requirements Planning (MRP) has been used extensively in manufacturing and other industries to improve on-time delivery and to reduce costs. In this paper, we illustrate how an MRP-type system was developed to monitor surgical linen at a large teaching hospital. We also describe a bar-code scanning 'tag and recapture' study to estimate total inventory. The hospital implemented several changes based upon our recommendations that resulted in time savings and a smoother flow of materials throughout the surgical linen supply chain.

Bedding and Linens↗
PubMed2001

The incidence of hydroxyethyl starch-associated pruritus.

BACKGROUND: Pruritus due to hydroxyethyl starch (HES) is reported with a very variable frequency but appears to be relatively uncommon in the U.K. compared with other European countries. OBJECTIVES: To determine the frequency of HES-related pruritus in patients discharged from intensive care units (ICUs) in two U.K. hospitals. METHODS: A questionnaire survey was given to 253 patients after discharge from ICU. Questions were designed to exclude pre-existing skin disease and other causes of pruritus. RESULTS: One hundred and fifty-nine completed questionnaires were suitable for analysis. Seventeen of 135 (12.6%) subjects who had received HES reported itch, as did one of 24 who had not received HES. There was no apparent relationship between the occurrence of HES-related pruritus and either the surgical indication or the brand or volume of HES infused. CONCLUSIONS: HES-related pruritus is a problem that dermatologists need to recognize; however, its frequency in the U.K., when other causes of itch are excluded, appears to be lower than suggested in some previous reported studies.

Drug Eruptions↗
PubMed2001

Fibroblast growth factors in the developing central nervous system.

1. It is now clear that members of the fibroblast growth factor (FGF) family have multiple roles during the formation of the central nervous system (CNS). 2. There are at least 23 members of the FGF family and, of these, 10 are expressed in the developing CNS, along with four FGF receptors (FGFR-1-4). 3. The present review discusses the roles of these FGFs, with emphasis on FGF-2, FGF-8, FGF-15 and FGF-17. Fibroblast growth factors-2 and -15 are generally expressed throughout the developing CNS, whereas FGF-8 and FGF-17 are tightly localized to specific regions of the developing brain and are only expressed in the embryo during the early phases of proliferation and neurogenesis. 4. Expression studies on FGFRs in the chick and mouse indicate that FGFR-1 is most generally expressed, whereas FGFR-2 and FGFR-3 show highly localized but changing patterns of expression throughout CNS development. The FGFR-4 has been localized to the developing CNS in fish but not at a detailed level, as yet, in chick or mouse. 5. A picture is emerging from these studies that particular FGFs signal through specific receptors in a highly localized manner to regulate the development of different regions of the brain. 6. This picture has been demonstrated so far for the developing cortex (FGF-2-/- mice), the forebrain and midbrain (FGF-8 hypomorphs) and the cerebellum (FGF-17/FGF-8 mutant mice). In addition, generation of mutant animals deleted for FGFR-1 and FGFR-2b IIIb demonstrate their importance in FGF signalling. 7. However, there are significant gaps in our knowledge of the localization of members of the FGF family and their receptors. More detailed information on the spatio-temporal mapping of FGFs and FGFR isoforms is required in order to understand the molecular mechanisms through which FGFs signal.

Animals↗
PubMed2001

An initial investigation of the reliability of the Rivermead Extended ADL index in patients presenting with neurological impairment.

The objective of this study was to establish the reliability and sensitivity of both postal and interviewer-administrated versions of the Rivermead Extended Activities of Daily Living (READL) index, which assesses six domestic activities and six community activities. Sixty patients with stable neurological impairment were recruited. In one group (n = 40), every patient was assessed face-to-face using the READL, the Barthel index (BI) and the short orientation memory and concentration test (SOMC). One week later, the READL was repeated by the same person, in the same place. In the second group (n = 20), all the patients were first sent a postal form of the READL and were then seen face-to-face for assessment as in group 1. To be included patients had to score at least 18/28 points on the SOMC. Scores were compared using scatterplots, Bland and Altman plots and correlation coefficients, and difference scores were calculated. Sensitivity was established comparing groups of patients expected to differ in their activities. Repeated assessment score, both face-to-face and by post, showed significant correlation (Pearson coefficient = 0.97 and 0.88, respectively). Most scores were within four points of each other, with no systematic bias, although patients tended to rate themselves more independent. Both methods were able to detect differences in the level of activities as predicted between more and less dependent groups (t-test: p < 0.00001 and p = 0.00087). The READL index appears to be a reliable and sensitive measure, with some evidence for validity, but further research is needed.

Activities of Daily Living↗
PubMed2001

The long form of CDK2 arises via alternative splicing and forms an active protein kinase with cyclins A and E.

We have reinvestigated the long form of cyclin-dependent kinase (CDK)2 that is expressed in many rodent cells. We show that the mRNA encoding CDK2L arises by alternative splicing and that the encoded protein can bind to, and be activated by, cyclins A and E. The complex of CDK2L with cyclin A has about half the specific activity of the equivalent CDK2-cyclin A complex. Also, CDK2L--cyclin A is inhibited to the same extent and by the same concentrations of p21(CIP1) as CDK2--cyclin A. The nucleotide sequences of intron V in the human and murine CDK2 genes, where the sequences encoding the 48-residue insert in CDK2L are located, show very high conservation in the position of the alternatively spliced exon and its surroundings. Despite this, we were not able to detect significant expression of CDK2L in human cell lines, although a low level is expressed in COS-1 cells from monkeys.

Alternative Splicing↗