Model-based Decision support in Diabetes Care

The model-based Karlsburg Diabetes Management System (KADIS^®) has been developed as a patient-focused decision-support tool to provide evidence-based advice for physicians in their daily efforts to optimize metabolic control in diabetes care of their patients on an individualized basis. For this purpose, KADIS^® was established in terms of a personalized, interactive in silico simulation procedure, implemented into a problem-related diabetes health care network and evaluated under different conditions by conducting open-label mono- and polycentric trials, and a case-control study, and last but not least, by application in routine diabetes outpatient care. The trial outcomes clearly show that the recommendations provided to the physicians by KADIS^® lead to significant improvement of metabolic control. This model-based decision-support system provides an excellent tool to effectively guide physicians in personalized decision-making to achieve optimal metabolic control for their patients.     

Investigations on the monolayer structure of thiol SAMs and the influence of conjugated π-bonds on the electronic molecular conductivity

Thiols have been in the focus of recent research because of their capability to form self assembled monolayers (SAM) on noble and semi-noble metals opening a new field of fundamental research and its application in various branches, as e.g. in nano technology. In this paper, the investigation of SAMs of six specially tailored thiols with an aromatic head group on a preferentially (1 1 1) orientated Au-surface are described with special interest in their structure and the electronic conductivity in dependence on the number of conjugated π-bonds in the chain group. Potentiodynamic polarization curves in 0.5 M KOH with and without [Fe(CN)₆]^3−/4− were used to obtain information on the quality and conductivity of the SAMs while scanning tunneling microscopy (STM) and XPS were used for investigations on the monolayer structure. Additionally molecular dynamic calculations were performed to check the possibility and reliability of these calculations to predict the arrangement of the thiol molecules within the SAMs. The electron conductivity of these SAMs rises significantly with the amount of conjugated π-bonds. A naphthalene head group causes the formation of SAMs with a typical herringbone structure whereas anthraquinone leads to a mixture of parallel and herringbone arrangements.     

Antibody response to islet antigens in anti-CD4/prednisolone immune intervention of type 1 diabetes

The O intermediate of the photocycle of bacteriorhodopsin (BR) was studied by absorption kinetic measurements at different actinic light densities. With increasing exciting flash intensity, the relative yield of O slightly increases, while that of Mf strongly decreases at the expense of Ms. Kinetic calculations and the optical anisotropy of O show that O can be formed only from Mf although Mf and O have different light intensity dependences. In order to resolve the apparent contradiction, a phenomenologically new cooperative regulatory mechanism seems to be necessary.     

Bilingual performance on the boston naming test: preliminary norms in Spanish and English

A total of 100 young educated bilingual adults were administered the Boston Naming Test (BNT) (Kaplan, Goodglass, & Weintraub, 1983) in both Spanish and English. Three group performance scores were obtained: English only, Spanish only, and a composite score indicating the total number of items correctly named independent of language. The scores for the entire group were significantly greater in English than in Spanish. An additional set of analyses explored individual differences in picture naming performance across the two languages as measured by the BNT. For a subset of the larger group (n = 25) there were significant differences in composite over single language scoring, but no significant differences between Spanish and English. Item analyses of correct responses were conducted in both languages to explore the construct validity of the standardized administration of the BNT with this population. There was much greater variability in responses over the Spanish items for this bilingual group. The results of a correlation analysis of information obtained from the initial questionnaire with the BNT scores in each language is also reported. The practical implications of this preliminary bilingual BNT normative data are discussed.     

Detection of autoantibodies to the 65-kD isoform of glutamate decarboxylase by radioimmunoassay

Antineutrophil cytoplasmic antibodies (ANCA) are autoantibodies mainly directed against alpha granules' components (especially proteinase 3 (PR 3) and myeloperoxidase (MPO). They are usually detected by indirect immunofluorescence (IIF) giving essentially two staining patterns, cytoplasmic and perinuclear. Nevertheless the IIF method does not allow to precise the true specificity of ANCA. From now on a better classification of systemic vasculitis requires such a determination. This can be done only by solid phase tests that require to be reliable, highly purified antigen, and, from a practical point of view, only a MPO-ELISA is currently available. We report on our experience with Western blot analysis of 67 IIF-ANCA positive sera. Using Western blot analysis to characterize ANCA specificity is not so easy as in the case of antibodies directed against extractable nuclear antigens: only PR 3 ANCA detection could be done reproducibly. PR 3 ANCA are mainly detected in the c-ACPN positive sera of patients with Wegener's granylomatosis. Nevertheless using both MPO-ELISA and PR 3 blot seems to increase the frequency of serum containing the two types of ANCA (anti PR 3 and anti MPO).     

Effect of disulfide bonds on the structure, function, and stability of the trypsin/tPA inhibitor from Erythrina caffra: site-directed mutagenesis, expression, and physiochemical characterization

Erythrina trypsin/tPA inhibitor (ETI) from the seeds of Erythrina caffra retains its native structure and inhibitory function after reducing its two disulfide bonds. In order to elucidate the specific role of these crosslinks, alanine residues were substituted for cysteines after cloning the gene in Escherichia coli. Expression of the recombinant inhibitor and the substitution mutants, C83A, CC39, 83AA, and CC132, 139AA, led to inclusion bodies. After solubilization in guanidinium-chloride (GdmCl)/dithiothreitol and oxidation in glutathione buffer, activity could be recovered at yields up to 80%. The mutant proteins exhibit full inhibitory function without detectable alterations of their native structure. However, their stability is reduced: at acid pH, where the oxidized natural inhibitor retains its native structure, the reduced wildtype protein and the mutants undergo at least partial denaturation, reflected by decreased pH ranges of stability: pH 5-7 for the reduced inhibitor, pH 2.5-8.5 for CC132, 139AA, and pH 3.5-8.5 for C83A and CC39, 83AA. Urea and GdmCl denaturation at pH 7 show hysteresis for both the oxidized inhibitor and the double mutant CC132, 139AA. In contrast, the reduced protein and the other mutants exhibit true equilibrium transitions at pH 7, with urea half-concentrations of 0.9 M and 1.9 M and GdmCl half-concentrations of 0.5 M and 1.0 M, respectively. The stability of Erythrina trypsin/tPA inhibitor follows the sequence: oxidized ETI > CC132, 139AA > CC39, 83AA and C83A > reduced ETI.     

Biochemical properties of the kringle 2 and protease domains are maintained in the refolded t-PA deletion variant BM 06.022

BM 06.022 is a t-PA deletion variant which comprises the kringle2 and the protease domain. Production of BM 06.022 in Escherichiacoli leads to the formation of inactive inclusion bodies, whichhave to be refolded by an in vitro refolding process to achieveactivity and proper structure of the domains. We analysed thebiochemical properties of BM 06.022 to obtain some informationabout the structure of kringle 2 and the protease as comparedwith the structure of these domains in the intact t-PA molecule.The kinetic analysis of the amidolytic activity of BM 06.022and CHO-t-PA yielded similar values for k_cat (13.9 s^-1and 11.4s^-1for the single chain forms and 33.9 s^-1and 27.1 s^-1for thetwo chain forms of BM 06.022 and CHO-t-PA, respectively) andfor k_m, (2.5 mM and 2.1 mM for the single chain forms and 0.5mM and 0.3 mM for the two chain forms of BM 06.022 and CHO-t-PA,respectively). BM 06.022 and CHO-t-PA have the same plasminogenolyticactivity in the absence of CNBr fragments of fibrinogen. However,BM 06.022 has a lower plasminogenolytic activity in the presenceof CNBr fragments of fibrinogen and a lower affinity to fibrinas compared with CHO-t-PA. The affinity of BM 06.022 for fibrinis completely suppressed by 0.3 mM eaminocaproic acid, whilethe intact t-PA has a residual affinity of 30%. The dissociationconstants for the interaction with the lysine analogue e-aminocaprokacid are 0.10 mM and 0.09 mM for BM 06.022 and the intact t-PA,respectively. Furthermore, BM 06.022 and CHO-t-PA are inhibitedby PAI-1 in a similar manner     

Structural mapping of the active site specificity determinants of human tissue-type plasminogen activator. Implications for the design of low molecular weight substrates and inhibitors

The recent structure determination of the catalytic domain of tissue-type plasminogen activator (tPA) suggested residue Arg174 could play a role in P3/P4 substrate specificity. Six synthetic chromogenic tPA substrates of the type R-Xaa-Gly-Arg-p-nitroanilide, in which R is an N-terminal protection group, were synthesized to test this property. Although changing the residue Xaa (in its L or D form) at position P3 from the hydrophobic Phe to an acidic residue, Asp or Glu, gave no improvement in catalytic efficiency, comparative analysis of the substrates indicated a preference for an acidic substituent occupying the S3 site when the S4 site contains a hydrophobic or basic moiety. The 2.9 A structure determination of the catalytic domain of human tPA in complex with the bis-benzamidine inhibitor 2, 7-bis-(4-amidinobenzylidene)-cycloheptan-1-one reveals a three-site interaction, salt bridge formation of the proximal amidino group of the inhibitor with Asp189 in the primary specificity pocket, extensive hydrophobic surface burial, and a weak electrostatic interaction between the distal amidino group of the inhibitor and two carbonyl oxygens of the protein. The latter position was previously occupied by the guanidino group of Arg174, which swings out to form the western edge of the S3 pocket. These data suggest that the side chain of Arg174 is flexible, and does not play a major role in the S4 specificity of tPA. On the other hand, this residue would modulate S3 specificity, and may be exploited to fine tune the specificity and selectivity of tPA substrates and inhibitors.     

Cytotoxic effects of islet cell surface antibodies

Antibodies against rat islet cells were produced by immunisation of rabbits with neonatal rat islet cells. In the presence of complement the rabbit anti-rat islet cell surface sera were strongly cytotoxic for both, neonatal rat islet cells and spleen lymphocytes as revealed by the high percentage of 51Cr release from these cells. However, after absorption with rat lymphocytes and rat liver powder the cytotoxicity of the islet cell antisera for rat lymphocytes was drastically reduced while the release of 51Cr from islet cells was only slightly influenced. These data indicate that islet cell specific antibodies were still present in the antisera after absorption. Native normal rabbit serum was also cytotoxic for neonatal rat islet cells and spleen lymphocytes. The release of 51Cr from islet cells and lymphocytes was vigorously reduced after absorption of the normal rabbit serum with lymphocytes and was paralleled by a similar decrease of insulin release from intact islets under conditions where the active insulin secretion was blocked pharmacologically. Intact islets prelabeled with 51Cr were also used as targets but this approach was less suitable for the detection of cytotoxic islet cell surface antibodies.