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Biological Marker

The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform

Youichirou Ootsuka – 1st expert on this subject based on the ideXlab platform

  • Clozapine, chlorpromazine and risperidone dose-dependently reduce emotional hyperthermia, a Biological Marker of salience
    Psychopharmacology, 2017
    Co-Authors: William W. Blessing, Esther M. Blessing, Mazher Mohammed, Youichirou Ootsuka

    Abstract:

    RationaleWe recently introduced a new rat model of emotional hyperthermia in which a salient stimulus activates brown adipose tissue (BAT) thermogenesis and tail artery constriction. Antipsychotic drugs, both classical and second generation, act to reduce excessive assignment of salience to objects and events in the external environment. The close association between salient occurrences and increases in body temperature suggests that antipsychotic drugs may also reduce emotional hyperthermia.ObjectivesWe determined whether chlorpromazine, clozapine, and risperidone dose dependently reduce emotionally elicited increases in BAT thermogenesis, cutaneous vasoconstriction, and body temperature in rats.MethodsRats, chronically instrumented for measurement of BAT and body temperature and tail artery blood flow, singly housed, were confronted with an intruder rat (confined within a small wire-mesh cage) after systemic pre-treatment of the resident rat with vehicle or antipsychotic agent. BAT and body temperatures, tail blood flow, and behavioral activity were continuously measured.ResultsClozapine (30 μg–2 mg/kg), chlorpromazine (0.1–5 mg/kg), and risperidone (6.25 μg–1 mg/kg) robustly and dose-relatedly reduced intruder-elicited BAT thermogenesis and tail artery vasoconstriction, with consequent dose-related reduction in emotional hyperthermia.ConclusionsChlorpromazine, a first-generation antipsychotic, as well as clozapine and risperidone, second-generation agents, dose-dependently reduce emotional hyperthermia. Dopamine D2 receptor antagonist properties of chlorpromazine do not contribute to thermoregulatory effects. Interactions with monoamine receptors are important, and these monoamine receptor interactions may also contribute to the therapeutic effects of all three antipsychotics. Thermoregulatory actions of putative antipsychotic agents may constitute a Biological Marker of their therapeutic properties.

  • clozapine chlorpromazine and risperidone dose dependently reduce emotional hyperthermia a Biological Marker of salience
    Psychopharmacology, 2017
    Co-Authors: William W. Blessing, Esther M. Blessing, Mazher Mohammed, Youichirou Ootsuka

    Abstract:

    Rationale
    We recently introduced a new rat model of emotional hyperthermia in which a salient stimulus activates brown adipose tissue (BAT) thermogenesis and tail artery constriction. Antipsychotic drugs, both classical and second generation, act to reduce excessive assignment of salience to objects and events in the external environment. The close association between salient occurrences and increases in body temperature suggests that antipsychotic drugs may also reduce emotional hyperthermia.

William W. Blessing – 2nd expert on this subject based on the ideXlab platform

  • Clozapine, chlorpromazine and risperidone dose-dependently reduce emotional hyperthermia, a Biological Marker of salience
    Psychopharmacology, 2017
    Co-Authors: William W. Blessing, Esther M. Blessing, Mazher Mohammed, Youichirou Ootsuka

    Abstract:

    RationaleWe recently introduced a new rat model of emotional hyperthermia in which a salient stimulus activates brown adipose tissue (BAT) thermogenesis and tail artery constriction. Antipsychotic drugs, both classical and second generation, act to reduce excessive assignment of salience to objects and events in the external environment. The close association between salient occurrences and increases in body temperature suggests that antipsychotic drugs may also reduce emotional hyperthermia.ObjectivesWe determined whether chlorpromazine, clozapine, and risperidone dose dependently reduce emotionally elicited increases in BAT thermogenesis, cutaneous vasoconstriction, and body temperature in rats.MethodsRats, chronically instrumented for measurement of BAT and body temperature and tail artery blood flow, singly housed, were confronted with an intruder rat (confined within a small wire-mesh cage) after systemic pre-treatment of the resident rat with vehicle or antipsychotic agent. BAT and body temperatures, tail blood flow, and behavioral activity were continuously measured.ResultsClozapine (30 μg–2 mg/kg), chlorpromazine (0.1–5 mg/kg), and risperidone (6.25 μg–1 mg/kg) robustly and dose-relatedly reduced intruder-elicited BAT thermogenesis and tail artery vasoconstriction, with consequent dose-related reduction in emotional hyperthermia.ConclusionsChlorpromazine, a first-generation antipsychotic, as well as clozapine and risperidone, second-generation agents, dose-dependently reduce emotional hyperthermia. Dopamine D2 receptor antagonist properties of chlorpromazine do not contribute to thermoregulatory effects. Interactions with monoamine receptors are important, and these monoamine receptor interactions may also contribute to the therapeutic effects of all three antipsychotics. Thermoregulatory actions of putative antipsychotic agents may constitute a Biological Marker of their therapeutic properties.

  • clozapine chlorpromazine and risperidone dose dependently reduce emotional hyperthermia a Biological Marker of salience
    Psychopharmacology, 2017
    Co-Authors: William W. Blessing, Esther M. Blessing, Mazher Mohammed, Youichirou Ootsuka

    Abstract:

    Rationale
    We recently introduced a new rat model of emotional hyperthermia in which a salient stimulus activates brown adipose tissue (BAT) thermogenesis and tail artery constriction. Antipsychotic drugs, both classical and second generation, act to reduce excessive assignment of salience to objects and events in the external environment. The close association between salient occurrences and increases in body temperature suggests that antipsychotic drugs may also reduce emotional hyperthermia.

Hans J. Nielsen – 3rd expert on this subject based on the ideXlab platform

  • circulating vegf as a Biological Marker in patients with rheumatoid arthritis preanalytical and Biological variability in healthy persons and in patients
    Disease Markers, 2008
    Co-Authors: Merete Lund Hetland, Ib Jarle Christensen, Tine Lottenburger, Julia S Johansen, M N Svendsen, Kim Horslevpetersen, L P Nielsen, Hans J. Nielsen

    Abstract:

    Background: Soluble vascular endothelial growth factor (VEGF) is a promising bioMarker in monitoring rheumatoid arthritis (RA), but studies of pre-analytical and biologic variability are few.

    Methods: VEGF was measured by ELISA methods in serum and plasma from healthy persons and RA patients. Pre-analytical factors were investigated. A reference interval for VEGF was established in serum and plasma from 306 healthy persons. Diurnal, day-to-day, week-to-week, long-term variability, and impact of exercise were evaluated.

    Results: Delayed processing time, room temperature, low centrifugal force and contamination of plasma with cellular elements lead to significant increases in VEGF levels, whereas storage for up to 2 years at −80°C or up to 10 freeze/thaw cycles did not affect VEGF levels. Serum VEGF levels were 7–10 fold higher than plasma VEGF levels. Reference intervals for VEGF (plasma: 45 pg/ml (range: non-detectable to 352); serum: 328 pg/ml (53–1791)) were independent of gender and age. Short- and long-term biologic variability included diurnal variation (sampling should take place after 7 AM) and impact of exercise (increased VEGF immediately after bicycling normalised within 1 hour).

    Conclusions: Pre-analytical factors and biologic variability including diurnal variation and impact of exercise should be accounted for in future studies that include circulating VEGF as a Biological Marker.

  • plasma tissue inhibitor of metalloproteinases 1 as a Biological Marker pre analytical considerations
    Clinica Chimica Acta, 2007
    Co-Authors: Anne F. Lomholt, Camilla B. Frederiksen, Ib Jarle Christensen, Nils Brünner, Hans J. Nielsen

    Abstract:

    Abstract Tissue Inhibitor of Metalloproteinases-1 (TIMP-1) may be a valuable Biological Marker in Colorectal Cancer (CRC). However, prospective validation of TIMP-1 as a Biological Marker should include a series of pre-analytical considerations. TIMP-1 is stored in platelets, which may degranulate during collection and storage. The aim of this study was to evaluate the influence of platelet TIMP-1 contamination on plasma TIMP-1 levels in healthy volunteers. Materials and methods All four parts of this study were done on EDTA-plasma. 1: The effect of stasis was evaluated in plasma collected with and without tourniquet. The collected whole blood was centrifuged at three different g-values. The effect of cellular contamination was evaluated 2: by adding plasma from just above the buffy-coat to one of four tubes containing plasma from the same sample and 3: by separating the plasma into three layers: upper, middle and lower. 4: The effect of temperature was studied by collection and handling of corresponding samples on ice and at room temperature. Prior to analysis samples were stored at − 80 °C. TIMP-1 was determined using a validated in-house ELISA. Results 1: TIMP-1 levels in plasma collected with or without stasis were not significantly different. Similarly TIMP-1 levels were not affected by the studied differences in centrifugation force. 2: TIMP-1 levels were significantly increased in plasma potentially contaminated with platelets (p  Conclusion Contamination with platelets during handling and storage of plasma may have significant effect on TIMP-1 levels. The results can define a standard operating procedure for sample collection and handling, which is important in obtaining uniform, comparable and reproducible plasma TIMP-1 levels.

  • Plasma tissue inhibitor of metalloproteinases-1 as a Biological Marker? Pre-analytical considerations
    Clinica Chimica Acta, 2007
    Co-Authors: Anne F. Lomholt, Camilla B. Frederiksen, Ib Jarle Christensen, Nils Brünner, Hans J. Nielsen

    Abstract:

    Tissue Inhibitor of Metalloproteinases-1 (TIMP-1) may be a valuable Biological Marker in Colorectal Cancer (CRC). However, prospective validation of TIMP-1 as a Biological Marker should include a series of pre-analytical considerations. TIMP-1 is stored in platelets, which may degranulate during collection and storage. The aim of this study was to evaluate the influence of platelet TIMP-1 contamination on plasma TIMP-1 levels in healthy volunteers. Materials and methods: All four parts of this study were done on EDTA-plasma. 1: The effect of stasis was evaluated in plasma collected with and without tourniquet. The collected whole blood was centrifuged at three different g-values. The effect of cellular contamination was evaluated 2: by adding plasma from just above the buffy-coat to one of four tubes containing plasma from the same sample and 3: by separating the plasma into three layers: upper, middle and lower. 4: The effect of temperature was studied by collection and handling of corresponding samples on ice and at room temperature. Prior to analysis samples were stored at – 80 °C. TIMP-1 was determined using a validated in-house ELISA. Results: 1: TIMP-1 levels in plasma collected with or without stasis were not significantly different. Similarly TIMP-1 levels were not affected by the studied differences in centrifugation force. 2: TIMP-1 levels were significantly increased in plasma potentially contaminated with platelets (p < 0.0001). 3: Separation of plasma into an upper, middle and lower layer did not affect the levels of plasma TIMP-1. 4: Samples kept at room temperature following collection showed significantly higher plasma TIMP-1 levels than samples kept on ice (p < 0.0001). Conclusion: Contamination with platelets during handling and storage of plasma may have significant effect on TIMP-1 levels. The results can define a standard operating procedure for sample collection and handling, which is important in obtaining uniform, comparable and reproducible plasma TIMP-1 levels. © 2007 Elsevier B.V. All rights reserved.