Stereochemistry, total synthesis, and biological activity of 14,15-dihydroxy-5,8,10,12-eicosatetraenoic acid

The stereochemistry of the major isomer of 14,15-dihydroxy-5,8,10,12-eicosatetraenoic acid formed from 15-hydroperoxyeicosatetraenoic acid in human leukocytes was determined. The structure (erythro-14(R),15(S]-14,15-dihydroxy-5,8-cis-10,12-trans-eicosatetraenoi c acid) was assigned based on sodium arsenite thin-layer chromatography, NMR spectroscopy, and comparison with material prepared by total synthesis. This compound was found to inhibit leukotriene B4-induced superoxide anion generation in human neutrophils (IC50 = 10(-8)-10(-7) M). Superoxide anion generation induced by either formylmethionyl-leucyl-phenylalanine or arachidonic acid was not affected.     

Helicobacter pylori Infection Induces Anemia,Depletes Serum Iron Storage,and Alters Local Iron-Related and Adult Brain Gene Expression in Male INS-GAS Mice

Iron deficiency anemia (IDA) affects > 500 million people worldwide, and is linked to impaired cognitive development and function in children. Helicobacter pylori, a class 1 carcinogen, infects about half of the world’s population, thus creating a high likelihood of overlapping risk. This study determined the effect of H. pylori infection on iron homeostasis in INS-GAS mice. Two replicates of INS-GAS/FVB male mice (n = 9-12/group) were dosed with H. pylori (Hp) strain SS1 or sham dosed at 6–9 weeks of age, and were necropsied at 27–29 weeks of age. Hematologic and serum iron parameters were evaluated, as was gene expression in gastric and brain tissues. Serum ferritin was lower in Hp SS1-infected mice than uninfected mice (p < 0.0001). Infected mice had a lower red blood cell count (p<0.0001), hematocrit (p < 0.001), and hemoglobin concentration (p <0.0001) than uninfected mice. Relative expression of gastric hepcidin antimicrobial peptide (Hamp) was downregulated in mice infected with Hp SS1 compared to sham-dosed controls (p<0.001). Expression of bone morphogenic protein 4 (Bmp4), a growth factor upstream of hepcidin, was downregulated in gastric tissue of Hp SS1-infected mice (p<0.001). Hp SS1-infected mice had downregulated brain expression of tyrosine hydroxylase (Th) (p = 0.02). Expression of iron-responsive genes involved in myelination (myelin basic protein (Mbp) and proteolipid protein 2 (Plp2)) was downregulated in infected mice (p = 0.001 and p = 0.02). Expression of synaptic plasticity markers (brain derived neurotrophic factor 3 (Bdnf3), Psd95 (a membrane associated guanylate kinase), and insulin-like growth factor 1 (Igf1)) was also downregulated in Hp SS1-infected mice (p = 0.09, p = 0.04, p = 0.02 respectively). Infection of male INS-GAS mice with Hp SS1, without concurrent dietary iron deficiency, depleted serum ferritin, deregulated gastric and hepatic expression of iron regulatory genes, and altered iron-dependent neural processes. The use of Hp SS1-infected INS-GAS mice will be an appropriate animal model for further study of the effects of concurrent H. pylori infection and anemia on iron homeostasis and adult iron-dependent brain gene expression.     

The Synthesis of Aminopyri Dine-Based Phosphonoacetates as ADP Analogs

Abstract

The rationale for proposing the title compounds as potential adenosine diphosphate receptor antagonists is discussed. A convenient synthesis and formulation for the cyclopentenyl amino alcohol 8 is described.     

Developmental regulation of protein synthesis during Polysphondylium pallidum cyst germination: A two-dimensional gel electrophoresis study

Microcyst germination in Polysphondylium pallidum can be used as a model for studying gene expression because temporally regulated modulations in protein synthesis occur in this developmental pathway. Germinating cysts were labeled with [³⁵S]methionine for half-hourly periods during the synchronous germination sequence, and the proteins labeled in each period were resolved by two-dimensional polyacrylamide gel electrophoresis. Three major classes of proteins observed were distinguished by the time of onset and duration of their synthesis: (a) proteins made throughout germination; (b) proteins synthesized only during a portion of the germination pathway; and (c) polypeptides whose synthesis started at 1 or 1.5 h and then continued throughout germination.     

Multiple genetic mechanisms have contributed to the generation of the HLA-A2/A28 family of class I MHC molecules

The genetic events that produce diversity in class I MHC genes and proteins has been investigated by using a family of closely related HLA-A alleles. Five genes coding for HLA-A2.2Y, HLA-A2.3, and HLA-Aw68.2 have been isolated. Exon sequences are compared with the known sequences for HLA-A2.1, HLA-A2.2F, HLA-A2.4, HLA-Aw68.1, and HLA-Aw69. Pairwise comparison of the eight unique sequences shows that point mutation, reciprocal recombination, and gene conversion have all contributed significantly to the diversification of this family of alleles. These results are compared with those of other studies that have emphasized the role of gene conversion. A predominance of coding substitutions in the alpha 1 and alpha 2 domains is found, consistent with positive selection for polymorphism being a major factor in the fixation of these alleles. In the three cases examined, genes for phenotypically identical proteins gave identical nucleotide sequences, indicating that most, if not all, of the class I polymorphism is detectable by immunological methods. The apparent stability of the sequences suggests that the events generating some of the alleles occurred before the origin of modern Homo sapiens.     

Synthesis of macromolecules during microcyst germination in the cellular slime mold Polysphondylium pallidum

Microcyst germination in the cellular slime mold Polysphondylium pallidum is a useful model for studying macromolecular changes necessary for or coincident with the transition from one cell type (cyst) to another (amoebae). Protein synthesis starts soon after cysts are incubated under permissive conditions, as evidenced by the incorporation of precursors and the appearance of polysomes. Sodium dodecyl sulfate-polyacrylamide gel analysis of proteins made at intervals during germination shows that protein synthesis is developmentally regulated during this process. RNA synthesis also begins early during germination. Cysts contain polyadenylated RNA that can stimulate the incorporation of radioactive amino acids into protein in an in vitro wheat germ protein synthesizing system. The concentration of poly(A)-containing RNA increases during germination and during inhibition of protein synthesis by cycloheximide.     

Inherited CAG.CTG allele length is a major modifier of somatic mutation length variability in Huntington disease

Huntington disease (HD) is associated with an unstable trinucleotide CAG.CTG repeat expansion. Although the repeat length is inversely correlated with the age-at-onset of symptoms, variability between patients who have inherited the same HD repeat length clearly suggests that other factors influence this aspect of the disease. As repeat length profiles in somatic tissues suggest that repeat length gains may contribute to both the tissue-specificity and progressive nature of HD pathogenesis, genetic modifiers of mutation length variability may therefore influence the age-at-onset of the disease. Using a sensitive single molecule-PCR assay we show that HD mutation length profiles in buccal cell DNA vary from individual to individual. The resulting data provide the first quantitative evidence that inherited CAG.CTG repeat length has a major influence on somatic CAG.CTG repeat length variation. In addition, we confirm that further environmental and/or genetic modifiers of repeat length variation exist and discuss the implications that our results may have on understanding the factors that influence severity and age-at-onset of Huntington disease symptoms.