The relationship between beta cell activation and SLC30A8/ZnT8 levels of the endocrine pancreas and maternal zinc deficiency in rats

ObjectivesZinc, which is found in high concentrations in the β-cells of the pancreas, is also a critical component for the endocrine functions of the pancreas. SLC30A8/ZnT8 is the carrier protein responsible for the transport of zinc from the cytoplasm to the insulin granules. The aim of this study was to investigate how dietary zinc status affects pancreatic beta cell activation and ZnT8 levels in infant male rats born to zinc-deficient mothers.MethodsThe study was performed on male pups born to mothers fed a zinc-deficient diet. A total of 40 male rats were divided into 4 equal groups. Group 1: In addition to maternal zinc deficiency, this group was fed a zinc-deficient diet. Group 2: In addition to maternal zinc deficiency, this group was fed a standard diet. Group 3: In addition to maternal zinc deficiency, this group was fed a standard diet and received additional zinc supplementation. Group 4: Control group. Pancreas ZnT8 levels were determined by ELISA method and insulin-positive cell ratios in β-cells by immunohistochemistry.ResultsThe highest pancreatic ZnT8 levels and anti-insulin positive cell ratios in the current study were obtained in Group 3 and Group 4. In our study, the lowest pancreatic ZnT8 levels were obtained in Group 1 and Group 2, and the lowest pancreatic anti-insulin positive cell ratios were obtained in Group 1.ConclusionThe results of the present study; in rats fed a zinc-deficient diet after maternal zinc deficiency has been established shows that ZnT8 levels and anti-insulin positive cell ratios in pancreatic tissue, which is significantly suppressed, reach control values with intraperitoneal zinc supplementation.     

Through-bond correlation of adenine H2 and H8 protons in unlabeled DNA fragments by HMBC spectroscopy

Summary A new application of the HMBC experiment is presented that provides a useful means to discriminate between H2 and H8 proton resonances, to assign the base proton resonances to the various residue types and, most importantly, to correlate the H2 and H8 protons for adenine or inosine residues in natural abundance ¹³C fragments. The utility of this experiment is demonstrated for an unlabeled DNA 20-mer. Thanks to the obtained results, preliminary conclusions could be drawn regarding the molecular conformations of the non-canonical G/I-A base pairs in the hairpin formed by this fragment.     

In vitro anti- and pro-oxidative effects of natural polyphenols

The anti- and pro-oxidative effects of phenolic compounds and antioxidants were studied in two different in vitro model systems utilizing ethyl linoleate and 2′-deoxyguanosine (2′-dG) as oxidative substrates, and a Fenton reaction (H₂O₂, Fe²⁺) to initiate oxidation. Oxidation of the biomolecules in both model systems exhibited dose dependency. In the 2′-dG assay, oxidation was closely related to H₂O₂ generation, which occurred during autoxidation of the phenolics. Hydroxylating activity was greatly enhanced by Mn²⁺ and Cu²⁺, but not by Zn²⁺ or Co²⁺. Ethyl linoleate peroxidation was inhibited by low concentrations of catechol, quercitin, and instant coffee. However, peroxidation was promoted by high concentrations of the same compounds, probably by recycling of chelated inactive Fe³⁺ to the active Fe²⁺ state.     

Oral administration of antigen does not influence the proliferation and IFN-γ production of responsive CD8+ T cells but enables to establish T cell clones with different lymphokine production profile.

Feeding of a whole casein diet, which abolished the α_s1-casein-specific proliferation and IFN-γ productivity of CD⁴⁺ T cells, did not affect the proliferative response of CD8⁺ T cells with regard to the antigen dose response, cell dose response, kinetics of the proliferation and epitope specificity, as well as IFN-γ production. To assess the characteristics of the CD8⁺ T cells, we established α_s1-casein-specific CD8⁺ T cell clones from both casein-fed and control mice. The established clones produced different amount of IFN-γ and IL-10, and one clone derived from the casein-fed mice produced a remarkable amount of IL-10. The clones from casein-fed mice produced considerable amounts of TGF-β, while those from control mice produced only small amounts. The possible role of CD8⁺ T cells in oral tolerance is discussed. This revised version was published online in June 2006 with corrections to the Cover Date.     

Analysis of clonality in cytologic material using the polymerase chain reaction (PCR)

Analysis of clonality in cytologic material using the polymerase chain reaction (PCR) Immunoglobulin heavy chain (IgH) gene rearrangement analysis was performed on 27 fine needle aspiration (FNA) specimens (13 reactive hyperplasia, 11 B cell non-Hodgkin's lymphoma (B-NHL), one Hodgkin's disease and two suspicious of non-Hodgkin's lymphoma). Satisfactory amplification was achieved in 23/27 cases. A polyclonal pattern was seen in 14 cases (11 reactive hyperplasia, one B-NHL, one suspicious of lymphoma, one Hodgkin's disease). A monoclonal band was seen in nine cases (eight B-NHL, one reactive hyperplasia). Amplification was unsuccessful in four cases. Clonal analysis by PCR-based IgH gene rearrangement analysis can be successfully applied to FNA material and can be useful in diagnosis, but the results must be interpreted in conjunction with morphology and other ancillary information. Analyse de la clonalité en utilisant la PCR sur matériel cytologique L'analyse des réarrangements géniques des chaînes lourdes des immunoglobulines (IgH) a été réalisée sur 27 produits de ponction à l'aiguille fine (13 cas d'hyperplasie réactionnelle, 11 cas de lymphome non hodgkinien de type B (LNH-B), un cas de maladie de Hodgkin et deux cas suspects de lymphome malin non hodgkinien. Une amplification satisfaisante a été obtenue dans 23 cas sur 27. Un aspect polychonal a été observé dans 14 cas (11 hyperplasies réactionnelles, 1 lymphome malin non hodgkinien de type B, 1 cas suspect de lymphome, 1 cas de maladie de Hodgkin). Une bande monoclonale a été observée dans 9 cas (8 LNH-B, 1 hyperplasie réactionnelle). L'amplification n'a pas réussi dans quatre cas. L'analyse de la clonalité par analyse des réarrangements géniques par PCR peut être appliquée avec succès au matériel cytologique qui est obtenu par ponction à l'aiguille fine et elle peut être utile au plan diagnostique, mais les résultats doivent étre interprétés en intégrant les informations morphologiques et les autres données complémentaires. Polymerase Chain Reaction an zytologischem Material Die Analyse schwerer Immunglobulinketten (IgH) wurde an 27 FNP (13 reaktive Hyperplasien, 11 B-NHL, 1 Hodgkin und und zwie verdächtige Fälle) analysiert. Eine ausreichende Amplifikation wurde in 23/27 Fällen erzielt. Ein polyklonales Muster wurde in 14 Fällen beobachtet (11 reaktive Hyperplasien, 1 B-NHL, 1 Hodgkin sowie 1 verdächtiger Fall). Ein monoklonales Band wurde 9 mal gefunden (8 B-NHL, 1 reaktive Hyperplasie). Die Amplifikation war ungenügend in 4 Fällen. Die PCR-Analyse kann für die Diagnostik von Nutzen sein muss jedoch zusammen mit der Morphologie und anderen Informationen interpretiert werden.     

Domain Evolution in the α-Amylase Family

The available amino acid sequences of the α-amylase family (glycosyl hydrolase family 13) were searched to identify their domain B, a distinct domain that protrudes from the regular catalytic (β/α)₈-barrel between the strand β3 and the helix α3. The isolated domain B sequences were inspected visually and also analyzed by Hydrophobic Cluster Analysis (HCA) to find common features. Sequence analyses and inspection of the few available three-dimensional structures suggest that the secondary structure of domain B varies with the enzyme specificity. Domain B in these different forms, however, may still have evolved from a common ancestor. The largest number of different specificities was found in the group with structural similarity to domain B from Bacillus cereus oligo-1,6-glucosidase that contains an α-helix succeeded by a three-stranded antiparallel β-sheet. These enzymes are α-glucosidase, cyclomaltodextrinase, dextran glucosidase, trehalose-6-phosphate hydrolase, neopullulanase, and a few α-amylases. Domain B of this type was observed also in some mammalian proteins involved in the transport of amino acids. These proteins show remarkable similarity with (β/α)₈-barrel elements throughout the entire sequence of enzymes from the oligo-1,6-glucosidase group. The transport proteins, in turn, resemble the animal 4F2 heavy-chain cell surface antigens, for which the sequences either lack domain B or contain only parts thereof. The similarities are compiled to indicate a possible route of domain evolution in the α-amylase family. Received: 4 December 1996 / Accepted: 13 March 1997     

Down-Regulation of T-Cell Proliferation in Response to Soluble Anti-CD3 Antibodies through Development of Redirected Cytolytic Activity Eliminating Costimulatory Cells

CD4⁺ T-depleted spleen cells (CD8⁺ T cells) activated by anti-CD3 antibodies (aCD3) suppressed proliferation of CD8⁺ T-depleted spleen cells (CD4⁺ T cells) and fresh normal T cells in response to aCD3. Antigen-nonspecific cytolytic activity was induced in splenic CD8⁺ T cells by stimulation with aCD3 and showed the peak level on day 3, whereas cytolytic activity induced in CD4⁺ T cells was weak. Intact Ig but not F(ab')₂ of aCD3 induced and mediated cytolytic activity. Correspondingly, the cytolytic activity induced by aCD3 was directed against target cells bearing Ig-binding Fc-receptor activity and cytolysis was inhibited by the addition of free Ig into the assay system. We showed that aCD3-activated T cells carried a high level of aCD3 on their surface at the time after the peak proliferation when they attained high cytolytic activity. This raised the possibility that the anti-CD3-induced aCD3-redirected cytolytic activity eliminated Fc-receptor-bearing costimulatory cells in the culture for down-regulation of the T-cell proliferation. This view was supported by partial restoration of anti-CD3-induced low responsiveness of CD8⁺ T cells by the addition of fresh costimulatory cells. These results suggested a new pathway of down-regulation of T-cell proliferation by aCD3-activated cytolytic CD8⁺ T cells.     

Sensitivity of Escherichia coli acrA mutants to psoralen plus near-ultraviolet radiation

The sensitivity to psoralen plus near-ultraviolet radiation (PUVA) was compared in a pair of E. coli strains differing at the acrA locus. Survival was determined for both bacteria and phage lambda. AcrA mutant cells were 40 times more sensitive than wild type to the lethal effect of PUVA. Free lambda phage exposed to PUVA survived as well when plated on acrA mutants as on wild type. In contrast, prophage lambda CI857 ind carried in lysogenic acrA strains was hypersensitive to PUVA. The enhanced sensitivity of bacterial and lambda DNA, when inside acrA cells, was paralleled by an increased photobinding of radiolabelled psoralens in the mutant. Binding was increased specifically to DNA rather than to nucleic acids in general. The difference in psoralen-binding ability determined by the acrA gene persisted after permeabilizing treatment of the cells. The results suggest that the acrA mutation causes an alteration specifically in the environment of the cellular DNA so as to allow increased intercalation and photobinding of psoralens.     

Aliphatic compounds from Costus speciosus roots

Two new compounds G and H isolated from the roots of Costus speciosus have been characterized as 8-hydroxytriacontan-25-one and Me tritriacontanoat