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Now showing items 1 - 16 of 33

  • Microtensiometry—A novel tool for fast drug solubility screening in 96-well plates

    L. Peltonen   S. Taskinen   J. Hirvonen  

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  • Microtensiometry—A novel tool for fast drug solubility screening in 96-well plates

    L. Peltonen   S. Taskinen    J. Hirvonen  

    The H+/peptide cotransporters PEPT1 and PEPT2 have gained considerable interest in pharmaceutical sciences as routes for drug delivery. It is, therefore, of interest to develop uncommon artificial substrates for the two carriers. This study was initiated to investigate the binding affinity of 2-aminothiazole-4-acetic acid (ATAA) conjugates with amino acids to PEPT1 and PEPT2. The 2-aminothiazole-4-acetic acid derivatives have been synthesised and tested for their affinity to PEPT1 and PEPT2. The Ki values were compared with in silico predicted values from CoMSIA models. C-terminal ATAA-Xaa conjugates proved to be low to medium inhibitors of the [14C]Gly-Sar uptake at both carrier systems whereas N-terminal Xaa-ATAA conjugates exhibited medium to high affinity. A promising candidate for further functionalisation is Val-ATAA which shows extraordinary high affinity to PEPT1.
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  • Serum IgE in non-atopic adults and in dermatitis patients

    L. Peltonen   V. K. Havu   L. Mattila  

    Total serum IgE was determined with the PRIST® technique, and specific reaginic antibodies against 10 allergens were measured in 163 healthy adults with no personal or family history of symptoms indicative of atopy (Group A). 103 non-atopic adults with a family history of atopic diseases were similarly investigated (Group B). When all subjects who at the second interview presented with a history of atopic symptoms and those with positive RAST results were excluded, the geometric mean serum IgE value for Group A was 14.5 (SD = 2) - 94.4 U/ml and for Group B 14.4 (SD = 2) - 130.2 U/ml. There was no significant difference in the IgE values between men and women. Subjects under 40 years of age had significantly higher IgE values than subjects over 40 years. In the series of 276 dermatitis patients the geometric mean IgE value for the men was significantly higher (46.8) than for the women (28.8 U/ml). There was a highly significant difference in the mean serum IgE levels between the patients with a personal history of atopic diseases and the other patients. Patients with present atopic disease had significantly higher mean IgE values than those with past atopic disease while no significant difference was discernible in the mean IgE levels between the non-atopic patients from atopic families and those with no personal and family atopy. Three years later, total serum IgE was controlled in subjects with initial IgE levels > 100 U/ml. During this time, eight subjects had developed an atopic disease. In most cases, there were only slight variations in the IgE values.
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  • Polymorphism of type I collagen genes in the Finnish population

    L. Peltonen   H. Ahti   A. Palotie   F. Ramirez  

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  • Congenital Fascial Dystrophy — A Noninflammatory Disease of Fascia: The Stiff Skin Syndrome

    S. Jablonska   J. Groniowski   T. Krieg   A. Nerlich   L. Peltonen   A. Oikarinen   J. Debrowski   D. Pietrow  

    Our patient's disease was similar to the persons with stiff skin syndrome described by Esterly and McKusick (1). Stony-hard indurations of the skin and deeper tissue were generalized but most pronounced in the buttocks, thighs, and legs, with limitation of joint mobility and particularly extensive contractures in the lower limbs. The disease was noticed when the patient was 18 months old, and was nonprogressive within a follow-up period of 12 years. There was no visceral involvement except functional impairment of the lungs, probably due to thickened thoracic fascia. Biochemical, histologic, and electron microscopic studies of the skin and muscle were not remarkable. In skin fibroblasts, collagen synthesis was increased and was accompanied by elevated activity of the prolylhydroxylase and lysylhydroxylase, whereas the transferases were not altered. The fascia was considerably thickened, but contained no inflammatory infiltrates. The significant electron microscopic finding was the presence of amianthoid-like collagen fibers in the fascia.
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  • Enzymes converting procollagens to collagens

    L. Peltonen   R. Halila   L. Ryh?nen  

    Conversion from [human] procollagen to collagen is a specific process that is a requirement for proper alignment of collagen molecules to form functional fibers. This process is catalyzed by at least 3 structurally and functionally distinct enzymes cleaving collagen types I-III. The cleavage processes possibly taking place in the more recently discovered collagen types are not known to any extent at this time. Two amino-terminal proteinases, one cleaving type I and type II procollagens and the other cleaving type III procollagen, were purified close to homogeneity, and the more unspecific activity of carboxy-terminal proteinase was isolated from several tissues. In the experimental model cleavage of the carboxy-terminal propeptides of types I and III procollagen is differently affected by Lys. This suggests the presence of at least 2 distinct enzymes for the removal of carboxyl-terminal propeptides. The regulation of the reaction process from procollagen to collagen is not well known at present. The importance of the phenomenon in terms of fibril formation is demonstrated by several elegant studies in vitro; and certain genetic disorders in which this process is defective demonstrate the significance in vivo. The factors shown to effect the cleavage process may be potentially beneficial in the treatment of the pathological processes with abnormal collagen accumulation such as fibrosis. The current knowledge of the converting enzymes is reviewed, including some very recent findings of this laboratory as well as the evidence presented for the biological significance of the conversion process.
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  • Prevalence of dichromate sensitivity Peltonen L, Fraki J: Contact Dermatitis 9:190, 1983

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  • Arylsulphatase in growing bones of rat

    L. Peltonen   L. K. Korhonen  

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  • Local cutaneous water barrier in cold- and heat-acclimated pigeons (Columba livia) in relation to cutaneous water evaporation

    L. Peltonen   Y. Arieli   R. Harjula   A. Py?rnil?   J. Marder  

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  • S5.2 – BBMRI

    L. Peltonen  

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  • K1

    L. Peltonen  

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  • K1

    L. Peltonen  

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  • Adaptive changes in the epidermal structure of the heat-acclimated rock pigeon (Columba livia): A comparative electron microscopy study

    L. Peltonen   Y. Arieli   A. Py?rnil?   J. Marder  

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  • Comparisons of computed two- and three-dimensional thermomechanical response of jointed rock : Johansson, E; Hakala, M; Peltonen, E; Salo, J P; Lorig, L J Proc 7th ISRM International Congress on Rock Mechanics, Aachen, 16–20 September 1991V1, P115–119. Publ Rotterdam: A A Balkema, 1991

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  • Gene defect behind APECED: a new clue to autoimmunity.

    P Björses   Jaakko Aaltonen   Nina Horelli-Kuitunen   M-L Yaspo   L. Peltonen  

    The molecular background of human autoimmunity is poorly understood. Although many autoimmune diseases have a genetic basis, the actual disease appearance results from a complex interplay between genes and environment and thus these diseases represent typical multifactorial diseases. Even with molecular tools provided by the Human Genome Project, it still remains a challenge to identify the predisposing DNA variants behind such multifactorial traits. Two strategies have been suggested to provide short-cuts to the dissection of the genetic background of complex autoimmune diseases: (i) identification of genes in rare human diseases with a strong autoimmune component or (ii) unravelling loci causing phenotypes resembling autoimmune diseases in inbred mice strains. Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is a monogenic autosomal disease with a recessive inheritance pattern, characterized by multiple autoimmune endocrinopathies, chronic mucocutaneous candidiasis and ectodermal dystrophies. Since it is the only known human autoimmune disease inherited in a Mendelian fashion, it provides an excellent model to analyse the genetic component of human autoimmunity. The causative gene for APECED was isolated recently by a traditional positional cloning strategy by two independent groups. The cDNA for the APECED gene proved to originate from a novel gene, AIRE , which is expressed prevalently in thymus, pancreas and adrenal cortex. Multiple mutations in AIRE have been identified in APECED patients. The predicted proline-rich AIRE polypeptide harbours two PHD-type zinc finger motifs and contains a putative nuclear targeting signal suggesting its involvement in the regulation of transcription. In the future, functional analysis of the AIRE protein both in vitro and in vivo will provide valuable insight not only into the molecular pathogenesis of APECED but also into the aetiology of autoimmunity in general.
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  • Polymer incorporation method affects the physical stability of amorphous indomethacin in aqueous suspension

    S.A. Surwase   L. Itkonen   J. Aaltonen   D. Saville   T. Rades   L. Peltonen   C.J. Strachan  

    Graphical abstract Abstract This study reports the potential of different polymers and polymer incorporation methods to inhibit crystallisation and maintain supersaturation of amorphous indomethacin (IND) in aqueous suspensions during storage. Three different polymers (poly(vinyl pyrrolidone) (PVP), hydroxypropyl methylcellulose (HPMC) and Soluplus® (SP)) were used and included in the suspensions either as a solid dispersion (SD) with IND or dissolved in the suspension medium prior to the addition of amorphous IND. The total concentrations of both IND and the polymer in the suspensions were kept the same for both methods of polymer incorporation. All the polymers (with both incorporation methods) inhibited crystallisation of the amorphous IND. The SDs were better than the predissolved polymer solutions at inhibiting crystallisation. The SDs were also better at maintaining drug supersaturation. SP showed a higher IND crystallisation inhibition and supersaturation potential than the other polymers. However, this depended on the method of addition. IND in SD with SP did not crystallise, nor did the SD generate any drug supersaturation, whereas IND in the corresponding predissolved SP solution crystallised (into the recently characterised η polymorphic form of the drug) but also led to a more than 20-fold higher IND solution concentration than that observed for crystalline IND. The ranking of the polymers with respect to crystallisation inhibition potential in SDs was SP ≫ PVP > HPMC. Overall, this study showed that both polymer type and polymer incorporation method strongly impact amorphous form stability and drug supersaturation in aqueous suspensions.
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