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  • 1
    Electronic Resource
    Electronic Resource
    Expression of glycogen synthase and phosphofructokinase in muscle from Type 1 (insulin-dependent) diabetic patients before and after intensive insulin treatment (1994)
    Springer
    Diabetologia 37 (1994), S. 82-90 
    Details
    ISSN: 1432-0428
    Keywords: Type 1 (insulin-dependent) diabetes mellitus ; gene expression ; skeletal muscle ; glycogen synthase ; phosphofructokinase ; hexokinase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The aim of the present study was to determine whether short-term appropriate insulinization of Type 1 (insulin-dependent) diabetic patients in longterm poor glycaemic control (HbA1C〉9.5%) was associated with an adaptive regulation of the activity and gene expression of key proteins in muscle glycogen storage and glycolysis: glycogen synthase and phosphofructokinase, respectively. In nine diabetic patients biopsies of quadriceps muscle were taken before and 24-h after intensified insulin therapy and compared to findings in eight control subjects. Subcutaneous injections of rapid acting insulin were given at 3-h intervals to improve glycaemic control in diabetic patients (fasting plasma glucose decreased from 20.8±0.8 to 8.7±0.8 mmol/l whereas fasting serum insulin increased from 59±8 to 173±3 pmol/l). Before intensified insulin therapy, analysis of muscle biopsies from diabetic patients showed a normal total glycogen synthase ctivity but a 48% decrease (p=0.006) in glycogen synthase fractional velocity (0.1 mmol/l glucose 6-phosphate) (FV0.1) and a 45% increase (p=0.01) in the half-maximal activation constant of glycogen synthase (A0.5). The activity of phosphofructokinase and the specific mRNA and immunoreactive protein levels of both glycogen synthase and phosphofructokinase were similar in the two groups. The 2.8-fold increase in serum insulin levels and the halving of the plasma glucose level for at least 15 h were associated with a normalization of glycogen synthase fractional activity (FV0.1) and of the half-maximal activation constant (A0.5) whereas the enzyme activity of phosphofructokinase and the mRNA and protein levels of both glycogen synthase and phosphofructokinase remained normal. In conclusion: 1) Reduced allosterical activation of glycogen synthase in muscle of Type 1 diabetic patients in poor metabolic control occurs in the presence of normal total activity as well as normal immunoreactive protein mass and mRNA level of glycogen synthase. 2) Changes in serum insulin within the physiological range play no role in the short-term regulation of glycogen synthase mRNA and protein abundance in muscle from Type 1 diabetic patients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00428782
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Unchanged gene expression of glycogen synthase in muscle from patients with NIDDM following sulphonylurea-induced improvement of glycaemic control (1995)
    Springer
    Diabetologia 38 (1995), S. 1230-1238 
    Details
    ISSN: 1432-0428
    Keywords: Non-insulin-dependent diabetes mellitus ; skeletal muscle ; glycogen synthase ; gene expression ; sulphonylurea treatment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have previously shown that the mRNA expression of muscle glycogen synthase is decreased in non-insulin-dependent diabetic (NIDDM) patients; the objective of the present protocol was to examine whether the gene expression of muscle glycogen synthase in NIDDM is affected by chronic sulphonylurea treatment. Ten obese patients with NIDDM were studied before and after 8 weeks of treatment with a weight-maintaining diet in combination with the sulphonylurea gliclazide. Gliclazide treatment was associated with significant reductions in HbA1c (p=0.01) and fasting plasma glucose (p=0.005) as well as enhanced beta-cell responses to an oral glucose load. During euglycaemic, hyperinsulinaemic clamp (2 mU · kg−1 · min−1) in combination with indirect calorimetry, a 35% (p=0.005) increase in whole-body insulin-stimulated glucose disposal rate, predominantly due to an increased non-oxidative glucose metabolism (p=0.02) was demonstrated in the gliclazide-treated patients when compared to pre-treatment values. In biopsies obtained from vastus lateralis muscle during insulin infusion, the half-maximal activation of glycogen synthase was achieved at a significantly lower concentration of the allosteric activator glucose 6-phosphate (p=0.01). However, despite significant increases in both insulin-stimulated non-oxidative glucose metabolism and muscle glycogen synthase activation in gliclazide-treated patients no changes were found in levels of glycogen synthase mRNA or immunoreactive protein in muscle. In conclusion, improved blood glucose control in gliclazide-treated obese NIDDM patients has no impact on the gene expression of muscle glycogen synthase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00422374
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Mutational analysis of the coding region of the uncoupling protein 2 gene in obese NIDDM patients: Impact of a common amino acid polymorphism on juvenile and maturity onset forms of obesity and insulin resistance (1997)
    Springer
    Diabetologia 40 (1997), S. 1227-1230 
    Details
    ISSN: 1432-0428
    Keywords: Keywords Uncoupling protein 2 ; obesity ; genetics ; insulin resistance ; amino acid polymorphism.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Recently, a gene encoding a novel human uncoupling protein, designated UCP2, was discovered. The murine UCP2 was mapped to a region on mouse chromosome 7 which in several models has been shown to be linked to obesity and hyperinsulinaemia. Single strand conformation polymorphism (SSCP) analysis and direct sequencing of the coding region of the UCP2 gene in 35 obese Caucasian NIDDM patients of Danish ancestry revealed one nucleotide substitution, replacing an alanine with a valine at codon 55. The amino acid polymorphism was present in 24 of the 35 (69 %) examined subjects. The allelic frequency of the A/V55 variant was 48.3 % (95 % CI: 42.5–54.1 %) among 144 subjects with juvenile onset obesity, 45.6 % (40.5–50.7 %) among 182 subjects randomly selected at the draft board examination, and 45.5 % (37.1–53.9 %) among lean control subjects selected from the same study cohort. Within these cohorts there were no differences in BMI values at different ages among wild-type carriers and A/V55 carriers. In a population-based sample of 369 young healthy Caucasians the variant showed no association with alterations in BMI, waist-to-hip ratio, fat mass or weight gain during childhood or adolescence. The A/V55 polymorphism was not related to alterations in fasting values of serum insulin and C-peptide or to an impaired insulin sensitivity index. We conclude that genetic variability in the human UCP2 gene is not a common factor contributing to NIDDM in obese Danish Caucasian subjects and the common A/V55 amino acid polymorphism of the gene is not implicated in the pathogenesis of juvenile or maturity onset obesity or insulin resistance in Caucasians. [Diabetologia (1997) 40: 1227–1230]
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001250050811
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Implications of compound heterozygous insulin receptor mutations in congenital muscle fibre type disproportion myopathy for the receptor kinase activation (1999)
    Springer
    Diabetologia 42 (1999), S. 245-249 
    Details
    ISSN: 1432-0428
    Keywords: Keywords Insulin receptor kinase ; compound heterozygous insulin receptor mutations ; human muscle ; erythrocytes ; congenital fibre type disproportion myopathy.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We studied insulin receptor kinase activation in two brothers with congenital muscle fibre type disproportion myopathy and compound heterozygous mutations of the insulin receptor gene, their parents, and their unaffected brother. In the father who has a heterozygote Arg1174→Gln mutation, in situ activation of the receptor kinase in skeletal muscle was reduced about 70 %. Selection of only those receptors that bound to anti-phosphotyrosine antibody showed that these receptors had normal kinase activity and that the reduction in overall kinase activity was due to the inability of about 70 % of the receptors to become insulin-dependently activated. The mother carries a point mutation at the last base pair in exon 17 which, due to abnormal alternative splicing, could lead to normally transcribed receptor or truncated receptor lacking the kinase region. Kinase activation was normal in the mother's skeletal muscle, suggesting that virtually no truncated receptor was expressed. Receptor kinase activity was, however, reduced by 95 and 91 % in the compound heterozygous brothers. This suggests that the mother's mutated allele contributes little to the generation of functional receptor protein and that the receptors in the mother's skeletal muscle are transcribed almost exclusively from the non-mutated allele. The mutation in exon 17 could lead to reduced transcription or rapid degradation of a predominantly transcribed truncated gene product or both. [Diabetologia (1999) 42: 245–249]
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001250051145
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Expression of glycogen synthase and phosphofructokinase in muscle from Type 1 (insulin-dependent) diabetic patients before and after intensive insulin treatment (1994)
    Springer
    Diabetologia 37 (1994), S. 82-90 
    Details
    ISSN: 1432-0428
    Keywords: Key words Type 1 (insulin-dependent) diabetes mellitus, gene expression, skeletal muscle, glycogen synthase, phosphofructokinase, hexokinase.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The aim of the present study was to determine whether short-term appropriate insulinization of Type 1 (insulin-dependent) diabetic patients in long-term poor glycaemic control (HbA1C〉9.5 %) was associated with an adaptive regulation of the activity and gene expression of key proteins in muscle glycogen storage and glycolysis: glycogen synthase and phosphofructokinase, respectively. In nine diabetic patients biopsies of quadriceps muscle were taken before and 24-h after intensified insulin therapy and compared to findings in eight control subjects. Subcutaneous injections of rapid acting insulin were given at 3-h intervals to improve glycaemic control in diabetic patients (fasting plasma glucose decreased from 20.8±0.8 to 8.7±0.8 mmol/l whereas fasting serum insulin increased from 59±8 to 173±3 pmol/l). Before intensified insulin therapy, analysis of muscle biopsies from diabetic patients showed a normal total glycogen synthase activity but a 48 % decrease (p =0.006) in glycogen synthase fractional velocity (0.1 mmol/l glucose 6-phosphate) (FV0.1) and a 45 % increase (p =0.01) in the half-maximal activation constant of glycogen synthase (A0.5). The activity of phosphofructokinase and the specific mRNA and immunoreactive protein levels of both glycogen synthase and phosphofructokinase were similar in the two groups. The 2.8-fold increase in serum insulin levels and the halving of the plasma glucose level for at least 15 h were associated with a normalization of glycogen synthase fractional activity (FV0.1) and of the half-maximal activation constant (A0.5) whereas the enzyme activity of phosphofructokinase and the mRNA and protein levels of both glycogen synthase and phosphofructokinase remained normal. In conclusion: 1) Reduced allosterical activation of glycogen synthase in muscle of Type 1 diabetic patients in poor metabolic control occurs in the presence of normal total activity as well as normal immunoreactive protein mass and mRNA level of glycogen synthase. 2) Changes in serum insulin within the physiological range play no role in the short-term regulation of glycogen synthase mRNA and protein abundance in muscle from Type 1 diabetic patients. [Diabetologia (1994) 37: 82–90]
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001250050076
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Chromosomal mapping and mutational analysis of the coding region of the glycogen synthase kinase-3α and β isoforms in patients with NIDDM (1997)
    Springer
    Diabetologia 40 (1997), S. 940-946 
    Details
    ISSN: 1432-0428
    Keywords: Keywords Southern hybridization ; in situ hybridization ; total RNA ; skeletal muscle ; RT-PCR-SSCP analysis ; mutations ; NIDDM.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Activation of glycogen synthesis in skeletal muscle in response to insulin results from the combined inactivation of glycogen synthase kinase-3 (GSK-3) and activation of the protein phosphatase-1, changing the ratio between the inactive phosphorylated state of the glycogen synthase to the active dephosphorylated state. In a search for genetic defects responsible for the decreased insulin stimulated glycogen synthesis seen in patients with non-insulin-dependent diabetes mellitus (NIDDM) and their glucose-tolerant first-degree relatives we have performed mutational analysis of the coding region of the 2 isoforms of GSK-3α and GSK-3β in 72 NIDDM patients and 12 control subjects. No structural changes were detected apart from a few silent mutations. Mapping of the GSK-3α to chromosome 19q13.1–13.2 and the GSK-3β to chromosome 3q13.3-q21 outside known genetic loci linked to NIDDM further makes it unlikely that these genes are involved in the pathogenesis of common forms of NIDDM. [Diabetologia (1997) 40: 940–946]
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001250050771
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Unchanged gene expression of glycogen synthase in muscle from patients with NIDDM following sulphonylurea-induced improvement of glycaemic control (1995)
    Springer
    Diabetologia 38 (1995), S. 1230-1238 
    Details
    ISSN: 1432-0428
    Keywords: Key words Non-insulin-dependent diabetes mellitus ; skeletal muscle ; glycogen synthase ; gene expression ; sulphonylurea treatment.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have previously shown that the mRNA expression of muscle glycogen synthase is decreased in non-insulin-dependent diabetic (NIDDM) patients; the objective of the present protocol was to examine whether the gene expression of muscle glycogen synthase in NIDDM is affected by chronic sulphonylurea treatment. Ten obese patients with NIDDM were studied before and after 8 weeks of treatment with a weight-maintaining diet in combination with the sulphonylurea gliclazide. Gliclazide treatment was associated with significant reductions in HbA1C (p = 0.01) and fasting plasma glucose (p = 0.005) as well as enhanced beta-cell responses to an oral glucose load. During euglycaemic, hyperinsulinaemic clamp (2 mU · kg–1· min–1) in combination with indirect calorimetry, a 35 % (p = 0.005) increase in whole-body insulin-stimulated glucose disposal rate, predominantly due to an increased non-oxidative glucose metabolism (p = 0.02) was demonstrated in the gliclazide-treated patients when compared to pre-treatment values. In biopsies obtained from vastus lateralis muscle during insulin infusion, the half-maximal activation of glycogen synthase was achieved at a significantly lower concentration of the allosteric activator glucose 6-phosphate (p = 0.01). However, despite significant increases in both insulin-stimulated non-oxidative glucose metabolism and muscle glycogen synthase activation in gliclazide-treated patients no changes were found in levels of glycogen synthase mRNA or immunoreactive protein in muscle. In conclusion, improved blood glucose control in gliclazide-treated obese NIDDM patients has no impact on the gene expression of muscle glycogen synthase. [Diabetologia (1995) 38: 1230–1238]
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00422374
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Double-blind, placebo-controlled food challenge with apple (2001)
    Copenhagen : Munksgaard International Publishers
    Allergy 56 (2001), S. 0 
    Details
    ISSN: 1398-9995
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The aim of the study was to develop and evaluate different methods of double-blind, placebo-controlled food challenge (DBPCFC) with apple. Three different DBPCFC models were evaluated: fresh apple juice, freshly grated apple, and freeze-dried apple powder. All challenges were performed outside the pollen season and took place from 1997 to 1999. The freeze-dried apple material was characterized by means of leukocyte histamine release (HR), skin prick test (SPT), and immunoblotting experiments. The study population consisted of birch pollen-allergic patients with a history of rhinitis in the birch-pollen season and positive specific IgE to birch. For comparison of the DBPCFC models, 65 patients with a positive open oral challenge with apple were selected. In the characterization of the freeze-dried apple material, 46 birch pollen-allergic patients were included. The IgE reactivity to apple was evaluated by measurement of specific IgE, HR, and SPT. Golden Delicious apples were used in all experiments. The results of this study showed that it was possible to perform DBPCFC with apple in birch pollen-allergic individuals. The model with freshly squeezed apple juice had a low sensitivity and displayed a high frequency of reactions to placebo, probably due to the ingredients used for blinding. The sensitivity of the models with freshly grated apple and freeze-dried apple powder was 0.74/0.60. An increase in sensitivity is desirable. The freeze-dried apple powder proved to be useful for SPT, HR, and oral challenges, but further investigation of the stability and the allergenic profile of the material is needed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1398-9995.2001.056002109.x
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    Paper (German National Licenses)
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