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  • Cell & Developmental Biology  (3)
  • Simulation  (2)
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Medical & biological engineering & computing 21 (1983), S. 710-717 
    ISSN: 1741-0444
    Schlagwort(e): Control ; Identification ; Least squares ; Muscle relaxants ; Simulation ; State estimation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Abstract A self-tuning algorithm is presented for the online control of muscle relaxation. Although some patient parameters were fixed at a mean value determined by offline analysis of patient data, certain parameters have been explicitly identified online. In addition the patient states are estimated and are used by a novel controller to bring an unrelaxed patient to some desired level of paralysis and maintain it. Simulations show that a twitch depression of 80% can be achieved in less than 20 min using d-tubocurarine without excessive overdosage.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Medical & biological engineering & computing 23 (1985), S. 556-564 
    ISSN: 1741-0444
    Schlagwort(e): Control ; Least squares ; Muscle relaxants ; Neuromuscular blockade ; Parameter estimation ; Simulation ; State estimation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Abstract An existing algorithm designed to control d-tubocurarine-induced muscle relaxation in humans has been evaluated in 38 clinical trials on patients undergoing upper and lower abdominal surgery. The data captured during these trials were used to perform offline analysis of the algorithm reported on here, by which the correct functioning of the algorthm was established and its efficacy rated. It is shown that, for practical purposes, the average controller performance is close to the theoretical limit which can be achieved for this drug. The use of online parameter estimation makes precise initialisation of the controller less critical than would be the case with a fixed control low. In the trials undertaken, an average time of 12 min was needed to reach the chosen set point and excessive overshoot was avoided in every case. With a setpoint for the single twitch response of 20 per cent of the control height, the average drug consumption for the first hour of operation was 0·38 mg kg−1.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 50 (1992), S. 161-169 
    ISSN: 0730-2312
    Schlagwort(e): chemoprevention ; in vitro models ; estradiol metabolism ; intermediate biomarker ; mammary preneoplasia ; Ras p21 ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: The animal models for chemoprevention of breast cancer have provided important experimental systems to evaluate the efficacy of tumor suppression by dietary macro-and micronutrients. In the initiation/promotion cascade, early occurring premalignant changes constitute less extensively examined aspects of disease progression. Molecular, endocrine and cellular biomarkers may provide clinically relevant endpoints for prevention of breast cancer that focus on downregulation of preneoplastic transformation. In vitro models derived from non-involved murine and human mammary tissues are utilized to identify molecular, endocrine and cellular markers that are perturbed in response to such diverse initiators as viruses and chemical carcinogens. This upregulation was manifested as persistant Ras p21-GTP binding, altered C16α/C2 hydroxylation of estradiol, and hyperplasia preceding tumorigenesis. Prototypic chemopreventive agents such as n-3 polyunsaturated fatty acids, retinoids, and indole-3-carbinol were capable of downregulating all of the preneoplastic markers perturbed by initiators. Experimental modulation of these biomarkers in murine and human mammary tissue prior to the expression of a fully transformed tumorigenic phenotype is suggestive of their potential clinical application in chemopreventive intervention for breast cancer. © 1992 Wiley-Liss, Inc. © 1992 Wiley-Liss, Inc.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    ISSN: 0730-2312
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Studies from this laboratory have demonstrated that negative modulation of the C-2/C-16α ratio of estradiol metabolites serves as a marker of the action of oncogenes and carcinogens which increase tumorigenicity, while positive modulation of this ratio measures the preventive effects of chemotherapeutic and chemopreventive agents on tumors and tumor cells. In order to facilitate human studies on chemopreventive agents and facilitate the measurement of this ratio, we have validated an ELISA assay using monoclonal antibodies developed by Immunocare, Inc., coated to 96-well plates.Urine samples (10λ) were diluted in buffer and hydrolyzed with mixed glucuronidase and sulfatase to cleave the conjugates. Aliquots of the hydrolysate were added to ELISA plates coated with the C-2 and C-16α antibodies respectively and the appropriate labeled antigens were added. After incubation the plates were washed, the color reagent added, and the plates read kinetically to determine the amount of compound present. A standard curve is run on each plate along with high and low standards. All samples were run in triplicate and the mean values determined. The ratios were computed automatically by the reader.Blind comparisons of duplicate urine samples showed a mean r value of 97%. Mean intra-assay variability was under 8% and inter-assay variability was under 10%.Studies involving diet modification and the differences between breast cancer patients and controls are underway.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 53 (1993), S. 256-256 
    ISSN: 0730-2312
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: A relationship between altered metabolism of estradiol (E2) and personal or familial risk for breast cancer suggests that endocrine changes associated with ovarian function may influence initiation or promotion of carcinogenesis. Evidence for a direct effect of E2 on non-involved mammary tissue (target for carcinogenesis) is equivocal. Explant cultures of human mammary terminal duct lobular units (TDLU) from breast cancer patients are utilized to examine whether (i) E2 metabolism in TDLU is altered in response to the chemical carcinogen benzo(a)pyrene [B(a)P], and (ii) perturbed E2 metabolism is modulated by naturally occurring polyunsaturated fatty acids (PUFA) and indole-3-carbinol (I3C). Treatment of TDLU with 40 nM B(a)P resulted in a 〉 95% decrease in C2/C16α-hydroxylation ratio of E2 relative to that detected in solvent controls. This metabolic alteration was due to a specific increase in E2 C16α-hydroxylation. Exposure of TDLU prior to and during B(a)P treatment with omega-6 PUFA decreased C2/C16α-hydroxylation ratio by 38% (p 〈 0.001). Treatment with omega-3 PUFA and I3C increased the ratio by 318% and 376% respectively (p 〈 0.001), due to a specific increase in E2 C2-hydroxylation. Thus, carcinogen-induced perturbation of E2 metabolism in TDLU and its modulation by dietary modulators of rodent mammary tumorigenesis provide evidence for this endocrine biomarker as a clinically relevant endpoint for chemoprevention of mammary carcinogenesis.
    Materialart: Digitale Medien
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