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  • plasma cortisol suppression  (3)
  • glutamic acid decarboxylase  (2)
  • immune histochemistry  (2)
  • 1
    ISSN: 1432-0428
    Keywords: Islet amyloid polypeptide ; human pancreatic islets ; islet transplantation ; immune histochemistry ; hyperglycaemia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Human islets of Langerhans were transplanted to the subcapsular space of the kidneys of nude mice which were either normoglycaemic or made diabetic with alloxan. After 2 weeks, the transplants were processed for light and electron microscopical analyses. In all transplants, islet amyloid polypeptide (IAPP)-positive cells were found with highest frequency in normoglycaemic animals. IAPP-positive amyloid was seen in 16 out of 22 transplants (73%), either by polarisation microscopy after Congo red staining or by immune electron microscopy. At variance with previous findings of amyloid deposits exclusively in the extracellular space of islets of non-insulin-dependent diabetic patients, the grafted islets contained intracellular amyloid deposits as well. There was no clear difference in occurrence of amyloid between diabetic and non-diabetic animals. The present study indicates that human islets transplanted into nude mice very soon present IAPP-positive amyloid deposits. This technique may provide a valuable model for studies of the pathogenesis of islet amyloid and its impact on islet cell function.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0428
    Keywords: Autoantigen ; glutamic acid decarboxylase ; insulin secretion ; diazoxide ; islet cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This study examined the relationship between insulin secretion and expression of the 64 kDa/glutamic acid decarboxylase autoantigen in pancreatic islets. Islets isolated from Wistar rats were cultured for 3 days under different conditions: in 5.5 mmol/l glucose with or without a-ketoisocaproic acid or glipizide and in 28 mmol/l glucose with or without diazoxide. The 64 kDa/glutamic acid decarboxylase autoantigen was precipitated from lysates of [35S]-methionine-labelled islets with sera from patients with Type 1 (insulin-dependent) diabetes mellitus and identified by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and fluorography. In parallel, insulin contents of the islets and the media were determined as well as the rates of glucose-stimulated (pro)insulin biosynthesis. α-Ketoisocaproic acid and glipi zide were found to stimulate the expression of the 64 kDa/glutamic acid decarboxylase autoantigen and also the rate of insulin secretion. Diazoxide on the other hand reduced the rate of the 64 kDa/glutamic acid decarboxylase autoantigen synthesis in parallel with an inhibition of glucose-stimulated insulin release. Under most of the conditions employed, (pro)insulin biosynthesis was not affected. The correlation found between the rate of insulin release and expression of the 64 kDa/glutamic acid decarboxylase auto-antigen might provide an explanation for the earlier observed relationship between the functional demands on the Beta cells and their rate of destruction which may result in diabetes.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0428
    Keywords: Type 1 (insulin-dependent) diabetes mellitus ; autoantigen ; glutamic acid decarboxylase ; NOD mouse ; islets of Langerhans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The presence of one of the major targets for auto-antibodies in Type 1 (insulin-dependent) diabetes mellitus, the enzyme glutamic acid decarboxylase, was studied in human, rat and mouse pancreatic tissue using immunoprecipitation and immunohistochemical techniques. Immunoprecipitation of glutamic acid decarboxylase was attempted with lysates of [35S]-methionine-labelled rat or mouse pancreatic islets using two different glutamic acid decarboxylase antisera, one mouse monoclonal antibody raised against the 65 kDa isoform of the enzyme, sera from six patients with Type 1 diabetes, one patient with stiff-man syndrome and sera from 19 non-obese diabetic mice. The same sera were used for immunoperoxidase staining of cryosections of human, rat or mouse pancreas. Using patient sera glutamic acid decarboxylase was detected by immunoprecipitations from isolated rat islets but not from islets of five different mouse strains tested, including the non-obese diabetic mouse. When using the non-obese diabetic mouse sera, glutamic acid decarboxylase could not be detected in either rat or mouse tissue. Immunoperoxidase staining demonstrated high levels of glutamic acid decarboxylase in human and rat pancreatic islets but low levels in mouse islets. Direct measurements of enzyme activity showed glutamic acid decarboxylase to be present in mouse islets at a level of about 40% of that in rat islets, and subsequent Western blot analyses indicated that mouse islets express the 67 kDa isoform, whereas in rat islets both the 67 and 65 kDa isoforms are present. The species difference at the level of one of the major islet cell autoantigens in Type 1 diabetes thus indicates that human or rat and mouse islets, respectively, express immunologically distinct forms of glutamic acid decarboxylase and differ in their way of regulating the enzyme production.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0428
    Keywords: Key words Islet amyloid polypeptide ; human pancreatic islets ; islet transplantation ; immune histochemistry ; hyperglycaemia.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Human islets of Langerhans were transplanted to the subcapsular space of the kidneys of nude mice which were either normoglycaemic or made diabetic with alloxan. After 2 weeks, the transplants were processed for light and electron microscopical analyses. In all transplants, islet amyloid polypeptide (IAPP)-positive cells were found with highest frequency in normoglycaemic animals. IAPP-positive amyloid was seen in 16 out of 22 transplants (73 %), either by polarisation microscopy after Congo red staining or by immune electron microscopy. At variance with previous findings of amyloid deposits exclusively in the extracellular space of islets of non-insulin-dependent diabetic patients, the grafted islets contained intracellular amyloid deposits as well. There was no clear difference in occurrence of amyloid between diabetic and non-diabetic animals. The present study indicates that human islets transplanted into nude mice very soon present IAPP-positive amyloid deposits. This technique may provide a valuable model for studies of the pathogenesis of islet amyloid and its impact on islet cell function. [Diabetologia (1995) 38: 543–549]
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-1041
    Keywords: Key words Corticosteroids; systemic effects ; plasma cortisol suppression ; white blood cell count ; healthy volunteers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract The systemic effects of single and multiple doses of inhaled fluticasone propionate (FP) and budesonide were examined in 24 healthy male volunteers (age range 18–29 years). The study was of an open, placebo-controlled, randomized, three-way crossover design. On each study day, multiple blood samples were taken over a 20 h period after drug administration (after a single dose and after the last of seven doses) and area under the curve (AUC0–20) for plasma cortisol and white blood cell (WBC) counts was calculated. Results: The present study shows that multiple dosing with FP 1.0 mg b.i.d. for 3.5 days (seven doses) resulted in a marked cortisol suppression from placebo which, at 55%, was more than double that seen with a single dose (25% suppression). Multiple dosing with budesonide 0.8 mg b.i.d. resulted in a 34% suppression in plasma cortisol compared with a suppression of 26% with a single dose. The increase in systemic activity of FP after multiple dosing is confirmed by both the number of subjects with 0800 hours plasma cortisol values below normal limits and by the changes in WBC and differential counts. Conclusion: The results of the present study confirm previous findings with regard to the more marked systemic effect of FP following multiple dosing as compared with a single dose. This increase in systemic effect from single dosing to multiple dosing is significantly greater for FP than for budesonide.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-1041
    Keywords: Corticosteroids ; systemic effects ; plasma cortisol suppression ; white blood cell count ; healthy volunteers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract The systemic effects of single and multiple doses of inhaled fluticasone propionate (FP) and budesonide were examined in 24 healthy male volunteers (age range 18–29 years). The study was of an open, placebo-controlled, randomized, three-way crossover design. On each study day, multiple blood samples were taken over a 20 h period after drug administration (after a single dose and after the last of seven doses) and area under the curve (AUC0–20) for plasma cortisol and white blood cell (WBC) counts was calculated. Results: The present study shows that multiple dosing with FP 1.0 mg b.i.d. for 3.5 days (seven doses) resulted in a marked cortisol suppression from placebo which, at 55%, was more than double that seen with a single dose (25% suppression). Multiple dosing with budesonide 0.8 mg b.i.d. resulted in a 34% suppression in plasma cortisol compared with a suppression of 26% with a single dose. The increase in systemic activity of FP after multiple dosing is confirmed by both the number of subjects with 0800 hours plasma cortisol values below normal limits and by the changes in WBC and differential counts. Conclusion: The results of the present study confirm previous findings with regard to the more marked systemic effect of FP following multiple dosing as compared with a single dose. This increase in systemic effect from single dosing to multiple dosing is significantly greater for FP than for budesonide.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-1041
    Keywords: Key words Fluticasone propionatei ; HPA-axis; bud esonide ; asthma ; children ; corticosteroids ; systemic effects ; plasma cortisol suppression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objective: To compare the systemic potency of inhaled fluticasone propionate delivered via Diskhaler® (FP-DH), and inhaled budesonide delivered via Turbuhaler® (BUD-TBH) over the clinically recommended dose range using plasma cortisol suppression as a marker for systemic activity. Methods: The systemic potency was examined in a dose-response study in 81 healthy male volunteers. The study was of an open, randomized, parallel-group (four groups) design, where two treatments were given in crossover fashion within each group. FP-DH and BUD-TBH were given b.i.d. for 7 days (14 doses): 100 and 100 μg (group 1); 200 and 200 μg (group 2); 500 and 400 μg (group 3); 1000 and 800 μg (group 4). There was a washout period of 7 days within each treatment group. All doses were administered at 08:00 and 20:00 hours. Multiple plasma cortisol samples were taken every 2 h over 24-h periods prior to randomization (baseline) and during steady state (i.e., the last two dosing intervals). Cortisol suppression was determined by comparing average plasma concentrations of cortisol before and during treatment. Dose-response curves for cortisol suppression were analyzed using multivariate non-linear regression (Hill modeling). Results: Multiple dosing for 7 days with FP-DH and BUD-TBH resulted in dose-dependent cortisol suppression by both drugs, most pronounced at the two highest dose levels. FP-DH-induced suppression was 41% at 500 μg and 86% at 1000 μg b.i.d., while that induced by BUD-TBH was 19% at 400 μg and 47% at 800 μg b.i.d. Statistically significant differences were found when comparing the two steroids at these two dose levels. Doses producing 50% of maximum suppression (ED50) were estimated at 833 μg b.i.d. for BUD-TBH and 479 μg b.i.d. for FP-DH. This gave an estimated relative cortisol suppression over the dose range of 1.74:1 (FP-DH:BUD-TBH). ED50 values, estimated from cortisol concentrations at 08:00 hours (12 h after the last dose), were 1212 μg b.i.d. for BUD-TBH and 527 μg b.i.d. for FP-DH giving a relative cortisol suppression of 2.30:1 (FP-DH:BUD-TBH). Fourteen subjects on the highest FP-DH dose and 3 at the next highest dose had morning plasma cortisol levels below the lower reference limit. No subject taking budesonide, however, had morning plasma cortisol levels below the reference limit. Analysis of the time for return to pretreatment baseline levels showed that cortisol suppression, 12–24 h after the last dose, was statistically significant compared with the baseline for the highest dose of FP-DH but not for any of the BUD-TBH doses. Conclusions: The results of the present study show that FP-DH suppresses plasma cortisol more than BUD-TBH on a equivalent basis with regard to both magnitude and duration.
    Type of Medium: Electronic Resource
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