Persson M

References (4)

Title : Vildagliptin enhances islet responsiveness to both hyper- and hypoglycemia in patients with type 2 diabetes - Ahren_2009_J.Clin.Endocrinol.Metab_94_1236
Author(s) : Ahren B , Schweizer A , Dejager S , Dunning BE , Nilsson PM , Persson M , Foley JE
Ref : J Clinical Endocrinology Metab , 94 :1236 , 2009
Abstract : CONTEXT: Dipeptidyl peptidase-4 inhibitors act by increasing plasma levels of glucagon-like peptide-1 and suppressing excessive glucagon secretion in patients with type 2 diabetes. However, their effects on the glucagon response to hypoglycemia are not established.
OBJECTIVE: The aim of the study was to assess effects of the dipeptidyl peptidase-4 inhibitor vildagliptin on alpha-cell response to hyper- and hypoglycemia. DESIGN: We conducted a single-center, randomized, double-blind, placebo-controlled, two-period crossover study of 28-d treatment, with a 4-wk between-period washout.
PATIENTS: We studied drug-naive patients with type 2 diabetes and baseline glycosylated hemoglobin of 7.5% or less.
INTERVENTION: Participants received vildagliptin (100 mg/d) or placebo as outpatients.
PRIMARY OUTCOME MEASURE(S): We measured the following: 1) change in plasma glucagon levels during hypoglycemic (2.5 mm glucose) clamp; and 2) incremental (Delta) glucagon area under the concentration-time curve from time 0 to 60 min (AUC(0-60 min)) during standard meal test. Before the study, it was hypothesized that vildagliptin would suppress glucagon secretion during meal tests and enhance the glucagon response to hypoglycemia.
RESULTS: The mean change in glucagon during hypoglycemic clamp was 46.7 +/- 6.9 ng/liter with vildagliptin treatment and 33.9 +/- 6.7 ng/liter with placebo; the between-treatment difference was 12.8 +/- 7.0 ng/liter (P = 0.039), representing a 38% increase with vildagliptin. In contrast, the mean glucagon DeltaAUC(0-60 min) during meal test with vildagliptin was 512 +/- 163 ng/liter x min vs. 861 +/- 130 ng/liter x min with placebo; the between-treatment difference was -349 +/- 158 ng/liter x min (P = 0.019), representing a 41% decrease with vildagliptin.
CONCLUSIONS: Vildagliptin enhances alpha-cell responsiveness to both the suppressive effects of hyperglycemia and the stimulatory effects of hypoglycemia. These effects likely contribute to the efficacy of vildagliptin to improve glycemic control as well as to its low hypoglycemic potential.
ESTHER : Ahren_2009_J.Clin.Endocrinol.Metab_94_1236
PubMedSearch : Ahren_2009_J.Clin.Endocrinol.Metab_94_1236
PubMedID: 19174497

Title : Collaborative meta-analysis of individual participant data from observational studies of Lp-PLA2 and cardiovascular diseases - Ballantyne_2007_Eur.J.Cardiovasc.Prev.Rehabil_14_3
Author(s) : Ballantyne C , Cushman M , Psaty B , Furberg C , Khaw KT , Sandhu M , Oldgren J , Rossi GP , Maiolino G , Cesari M , Lenzini L , James SK , Rimm E , Collins R , Anderson J , Koenig W , Brenner H , Rothenbacher D , Berglund G , Persson M , Berger P , Brilakis E , McConnell JP , Sacco R , Elkind M , Talmud P , Cannon CP , Packard C , Barrett-Connor E , Hofman A , Kardys I , Witteman JC , Criqui M , Corsetti JP , Rainwater DL , Moss AJ , Robins S , Bloomfield H , Collins D , Wassertheil-Smoller S , Ridker P , Danesh J , Gu D , Nelson JJ , Thompson S , Zalewski A , Zariffa N , Di Angelantonio E , Kaptoge S , Thompson A , Walker M , Watson S , Wood A
Ref : Eur J Cardiovasc Prev Rehabil , 14 :3 , 2007
Abstract : BACKGROUND: A large number of observational epidemiological studies have reported generally positive associations between circulating mass and activity levels of lipoprotein-associated phospholipase A2 (Lp-PLA2) and the risk of cardiovascular diseases. Few studies have been large enough to provide reliable estimates in different circumstances, such as in different subgroups (e.g., by age group, sex, or smoking status) or at different Lp-PLA2 levels. Moreover, most published studies have related disease risk only to baseline values of Lp-PLA2 markers (which can lead to substantial underestimation of any risk relationships because of within-person variability over time) and have used different approaches to adjustment for possible confounding factors. OBJECTIVES: By combination of data from individual participants from all relevant observational studies in a systematic 'meta-analysis', with correction for regression dilution (using available data on serial measurements of Lp-PLA2), the Lp-PLA2 Studies Collaboration will aim to characterize more precisely than has previously been possible the strength and shape of the age and sex-specific associations of plasma Lp-PLA2 with coronary heart disease (and, where data are sufficient, with other vascular diseases, such as ischaemic stroke). It will also help to determine to what extent such associations are independent of possible confounding factors and to explore potential sources of heterogeneity among studies, such as those related to assay methods and study design. It is anticipated that the present collaboration will serve as a framework to investigate related questions on Lp-PLA2 and cardiovascular outcomes. METHODS: A central database is being established containing data on circulating Lp-PLA2 values, sex and other potential confounding factors, age at baseline Lp-PLA2 measurement, age at event or at last follow-up, major vascular morbidity and cause-specific mortality. Information about any repeat measurements of Lp-PLA2 and potential confounding factors has been sought to allow adjustment for possible confounding and correction for regression dilution. The analyses will involve age-specific regression models. Synthesis of the available observational studies of Lp-PLA2 will yield information on a total of about 15 000 cardiovascular disease endpoints.
ESTHER : Ballantyne_2007_Eur.J.Cardiovasc.Prev.Rehabil_14_3
PubMedSearch : Ballantyne_2007_Eur.J.Cardiovasc.Prev.Rehabil_14_3
PubMedID: 17301621
Gene_locus related to this paper: human-PLA2G7

Title : Mutants provide evidence of the importance of glycosydic chains in the activation of lipase 1 from Candida rugosa - Brocca_2000_Protein.Sci_9_985
Author(s) : Brocca S , Persson M , Wehtje E , Adlercreutz P , Alberghina L , Lotti Marina
Ref : Protein Science , 9 :985 , 2000
Abstract : Sequence analysis of Candida rugosa lipase 1 (LIP1) predicts the presence of three N-linked glycosylation sites at asparagine 291, 314, 351. To investigate the relevance of sugar chains in the activation and stabilization of LIP1, we directed site mutagenesis to replace the above mentioned asparagine with glutamine residues. Comparison of the activity of mutants with that of the wild-type (wt) lipase indicates that both 314 and 351 Asn to Gln substitutions influence, although at a different extent, the enzyme activity both in hydrolysis and esterification reactions, but they do not alter the enzyme water activity profiles in organic solvents or temperature stability. Introduction of Gln to replace Asn351 is likely to disrupt a stabilizing interaction between the sugar chain and residues of the inner side of the lid in the enzyme active conformation. The effect of deglycosylation at position 314 is more difficult to explain and might suggest a more general role of the sugar moiety for the structural stability of lipase 1. Conversely, Asn291Gln substitution does not affect the lipolytic or the esterase activity of the mutant that behaves essentially as the wt enzyme. This observation supports the hypothesis that changes in activity of Asn314Gln and Asn351Gln mutants are specifically due to deglycosylation.
ESTHER : Brocca_2000_Protein.Sci_9_985
PubMedSearch : Brocca_2000_Protein.Sci_9_985
PubMedID: 10850808

Title : Alcohol and polyol dehydrogenases are both divided into two protein types, and structural properties cross-relate the different enzyme activities within each type - Jornvall_1981_Proc.Natl.Acad.Sci.U.S.A_78_4226
Author(s) : Jornvall H , Persson M , Jeffery J
Ref : Proc Natl Acad Sci U S A , 78 :4226 , 1981
Abstract : Sorbitol dehydrogenase from sheep liver shows similarities to mammalian and yeast alcohol dehydrogenases. Comparisons based on peptides from segments of sorbitol dehydrogenase reveal that homologous regions with 38% identity include two ligands to the active site zinc atom in liver alcohol dehydrogenase, as well as further important residues. Similarities in in other regions are less extensive, exactly as they are between different alcohol dehydrogenases. In all aspects, sorbitol dehydrogenase appears as a typical member of the alcohol dehydrogenase family. On the other hand, alcohol dehydrogenase from Drosophila, which has a shorter subunit, is not closely related to either of these enzymes, except for a region that probably corresponds to the first part of the coenzyme binding domain in many dehydrogenases. Instead, Drosophila alcohol dehydrogenase in its supposed catalytic region shows similarities toward Klebsiella ribitol dehydrogenase, which also has a small subunit. It may be concluded that both alcohol and polyol dehydrogenases show two types of protein subunit, reflecting an early subdivision of polypeptide types into "long" and "short" subunits rather than into different enzymatic specificities or quaternary structures. The relationships explain known properties of all these enzymes and provide insight into functional mechanisms and evolutionary interpretations.
ESTHER : Jornvall_1981_Proc.Natl.Acad.Sci.U.S.A_78_4226
PubMedSearch : Jornvall_1981_Proc.Natl.Acad.Sci.U.S.A_78_4226
PubMedID: 7027257