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  • 1
    Electronic Resource
    Electronic Resource
    Biological effects of encapsulated insulin on transfected Chinese hamster ovary cells (1995)
    Springer
    Diabetologia 38 (1995), S. 180-186 
    Details
    ISSN: 1432-0428
    Keywords: Insulin pharmacology ; insulin metabolism ; oral administration ; dose-response relationship ; cultured cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Oral administration of insulin incorporated into the wall of isobutylcyanoacrylate nanocapsule to diabetic rats induces a long-lasting normalization of their fasting glycaemia. In this study, we examined the biological action of encapsulated insulin on DNA and glycogen syntheses in Chinese hamster ovary cells transfected with the human insulin receptor gene. In the 10−11 mol/l–10−9 mol/l concentration range, encapsulated insulin elicited responses comparable to those induced by native insulin: at 10−9 mol/l, the rates of glycogen and DNA synthesis were enhanced by factors 3 and 2.5, respectively. Encapsulated insulin at 10−7 mol/l evoked receptor desensitization although it did not induce receptor down-regulation and did not alter receptor recycling for up to 6 h. Chloroquine decreased the action of native insulin on glycogen synthesis, but did not affect the dose-response characteristics of encapsulated insulin. Acid-washing of the cells after 1 h of stimulation decreased maximal insulin responsiveness and provoked a dose response curve for encapsulated insulin similar to that of the native hormone. Direct measurement of effective insulin binding activity showed that encapsulated insulin (at 10−8 and 10−7 mol/l) was withdrawn from the incubation medium 5–8 times less efficiently than native insulin. These data are in agreement with previous results showing that the polymeric wall protects encapsulated insulin from degradation. Persistence of intact encapsulated insulin inside and outside the cell may result in modifying signalling events and thus be responsible for the observed cellular desensitization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00400092
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    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Biological effects of encapsulated insulin on transfected Chinese hamster ovary cells (1995)
    Springer
    Diabetologia 38 (1995), S. 180-186 
    Details
    ISSN: 1432-0428
    Keywords: Key words Insulin pharmacology ; insulin metabolism ; oral administration ; dose-response relationship ; cultured cells.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Oral administration of insulin incorporated into the wall of isobutylcyanoacrylate nanocapsule to diabetic rats induces a long-lasting normalization of their fasting glycaemia. In this study, we examined the biological action of encapsulated insulin on DNA and glycogen syntheses in Chinese hamster ovary cells transfected with the human insulin receptor gene. In the 10–11 mol/l – 10–9 mol/l concentration range, encapsulated insulin elicited responses comparable to those induced by native insulin: at 10–9 mol/l, the rates of glycogen and DNA synthesis were enhanced by factors 3 and 2.5, respectively. Encapsulated insulin at 10–7 mol/l evoked receptor desensitization although it did not induce receptor down-regulation and did not alter receptor recycling for up to 6 h. Chloroquine decreased the action of native insulin on glycogen synthesis, but did not affect the dose-response characteristics of encapsulated insulin. Acid-washing of the cells after 1 h of stimulation decreased maximal insulin responsiveness and provoked a dose response curve for encapsulated insulin similar to that of the native hormone. Direct measurement of effective insulin binding activity showed that encapsulated insulin (at 10–8 and 10–7 mol/l) was withdrawn from the incubation medium 5–8 times less efficiently than native insulin. These data are in agreement with previous results showing that the polymeric wall protects encapsulated insulin from degradation. Persistence of intact encapsulated insulin inside and outside the cell may result in modifying signalling events and thus be responsible for the observed cellular desensitization.[Diabetologia (1995) 38: 180–186]
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00400092
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Assessment of high-frequency neonatal ventilator performances (1997)
    Springer
    Intensive care medicine 23 (1997), S. 208-213 
    Details
    ISSN: 1432-1238
    Keywords: Key words High-frequency ventilation ; Pediatric intensive care
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Objective: To assess the efficacy and reliability of neonatal high-frequency ventilators. Design: Bench evaluation of neonatal high-frequency ventilators. Setting: Physiology department and university hospital neonatal intensive care unit. Interventions: HFV-Babylog 8000 (Dräger Medical), OHF 1 (Dufour), and SensorMedics 3100A (SensorMedics) ventilators were connected to a neonatal test-lung. Tidal volume, peak-to-peak pressure amplitude, and mean airway pressure were measured for several ventilator settings, endotracheal tube sizes, and lung compliances. Measurements and results: Increasing peak-to-peak pressure resulted in a linear increase in tidal volume delivery in the 0–30% range of maximum amplitude. No significant increase in tidal volume was observed with the HFV-Babylog8000 when pressure amplitude was above 50%. The maximum tidal volume delivered was substantially smaller with the HFV-Babylog8000 than with the OHF1 or SensorMedics3100A. Tidal volume increased with endotracheal tube size with all three ventilators. Increasing test-lung compliance resulted in lower tidal volumes only with OHF1. Decreasing mean airway pressure was responsible for a decrease in tidal volume delivery with HFV-Babylog8000. Conclusion: We found that under our test conditions two of the three ventilators delivered adequate tidal volumes at the usual frequency of 15Hz, regardless of the size of the endotracheal tube and of the mechanical properties of the respiratory system. When lung compliance increased or mean airway pressure decreased, both of which are common events during the recovery phase of hyaline membrane disease, we found that the intrinsic properties of two of the ventilators tested were responsible for a decrease in tidal volume. This decrease may account for some cases of heretofore unexplained hypercapnia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001340050318
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Assessment of neonatal ventilator performances (1995)
    Springer
    Intensive care medicine 21 (1995), S. 753-758 
    Details
    ISSN: 1432-1238
    Keywords: Artificial ventilation ; Pediatric intensive care ; Positive end-expiratory pressure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Objective To analyze efficiency and reliability of 4 modern neonatal ventilators under difficult test conditions. The ventilators tested were: Babylog 8000 (Dräger Medical), BP 2001 (Bear Medical Systems), Sechrist IV 100 B (Sechrist Industries), Infant Star (Infrasonics INC). Measurements and results Gas flow generation was tested by comparison of preset flow values with no resistance in the circuit to flow values obtained during interposition of a resistance in the inspiratory circuit. A decrease in gas flow was observed when interposition of a resistance in the inspiratory circuit increased peak inspiratory pressure to 60 cmH2O (gas flow decreased by 8% to 24% depending on the ventilator tested). The pressure limiting valve and the positive end-expiratory pressure valve were also evaluated in order to test their behaviour under different flow conditions. Flow-dependence of the pressure was noted for all ventilators except Babylog 8000. Assessment of the reliability of pressure monitoring revealed either ‘under’ or ‘over’ estimation of peak inspiratory pressure and positive end-expiratory pressure depending on the ventilator tested. Conclusion For the best clinical use of mechanical ventilators, neonatologists should be aware of these limitations. Therefore a regular assessment of ventilator performance and monitoring reliability is recommended.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01704743
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    Paper (German National Licenses)
    Fulltext
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