Insulin and insulin-like growth factor-1 promote mast cell survival via activation of the phosphatidylinositol-3-kinase pathway

OBJECTIVE: Mast cells (MCs) play central roles for the onset and development of immediate-type and inflammatory allergic reactions. Since the inverse relationship between atopic disorders and diabetes mellitus has been observed in animals and humans, we investigated the effects of insulin (Ins) on MC signaling and biological function. METHODS: In bone marrow-derived MCs (BMMCs) from wild-type as well as SHIP-deficient mice Ins as well as insulin-like growth factor-1 (IGF-I)-triggered intracellular signaling events and MC effector functions were studied. RESULTS: We found that the addition of either Ins or IGF-1 to BMMCs triggers the phosphorylation of protein kinase B (PKB) and p38 kinase but not extracellular signal-regulated kinase (Erk). We also found that Ins/IGF-1 stimulates the tyrosine phosphorylation of SHIP1 and, in keeping with this, Ins/IGF-1-induced PKB phosphorylation is higher in SHIP1-/- BMMCs and is inhibited in SHIP+/+ as well as SHIP1-/- BMMCs with inhibitors of phosphatidylinositol-3-kinase (PI3K). Ins/IGF-1, like antigen (Ag), also stimulates the Rac-dependent activation of PAK as well as the production of hydrogen peroxide (H2O2). To elucidate the role of Ins and IGF-1 in MC biology, we studied their effects on Ag-mediated degranulation and MC survival. Although both only slightly enhanced Ag-mediated degranulation, they significantly promoted MC survival in the absence of IL-3 in a PI3K-dependent manner. CONCLUSION: The promotion of BMMC survival by induction of Ins/IGF-1 signaling may, in part, be responsible for the inverse correlation observed between atopic disorders and diabetes mellitus.     

Pattern of tau isoforms expression during development in vivo

Neuronal morphology and axonal growth during development are correlated to specific expression of various microtubule-associated protein tau isoforms. Using RT-PCR and Western blotting we found the unexpected result that the shift from fetal towards adult isoforms does not differ between rat cerebral cortex and cerebellum, two temporally differently developing areas. By immunohistochemistry we observed a cell type specific isoform expression during development and adulthood. The developmental expression of tau isoforms was compared to the appearance of stable microtubules assessed by the immunohistochemical detection of tubulin modifications. The tau isoform shift shows an apparent disconnect to neurogenesis, migration and volume growth, but coincides with the formation of synapses and the appearance of stable microtubules.     

Screening Trauma Patients With the Alcohol Use Disorders Identification Test and Biomarkers of Alcohol Use

Background:  Alcohol screening and brief interventions have been shown to reduce alcohol-related morbidity in injured patients. Use of self-report questionnaires such as the Alcohol Use Disorder Identification Test (AUDIT) is recommended as the optimum screening method. We hypothesized that the accuracy of screening is enhanced by combined use of the AUDIT and biomarkers of alcohol use in injured patients.
Methods:  The study was conducted in the emergency department of a large, urban, university hospital. Patients were evaluated with the AUDIT, and blood sampled to determine carbohydrate-deficient transferrin, gamma-glutamyl-transferase, and mean corpuscular volume. Alcohol problems were defined as presence of ICD-10 criteria for dependence or harmful use, or high-risk drinking according to World Health Organization criteria (weekly intake >420 g in males, >280 g in females). Screening accuracy was determined using Receiver Operating Characteristic curves.
Results:  There were 787 males and 446 females in the study. Median age was 33 years. The accuracy of the AUDIT was good to excellent, whereas all biomarkers performed only fairly to poorly in males, and even worse in females. At a specificity >0.80, sensitivity for all biomarkers was <0.43, whereas sensitivity for the AUDIT was 0.76 for males and 0.81 for females. The addition of biomarkers added little additional discriminatory information compared to use of the AUDIT alone.
Conclusions:  Screening properties of the AUDIT are superior to %CDT, MCV, and GGT for detection of alcohol problems in injured patients and are not clinically significantly enhanced by the use of biomarkers.     

Novel ALG8 mutations expand the clinical spectrum of congenital disorder of glycosylation type Ih

Congenital disorders of glycosylation (CDG) are an expanding group of inherited disorders caused by defects in the N- or O-Glycosylation of proteins and lipids. Several CDG subtypes have been described so far, including CDG type Ih which is caused by a deficiency of the dolichyl-P-Glc:Glc₁Man₉GlcNAc₂-PP-dolichyl α1,3-glucosyltransferase (hALG8). The defect leads to an accumulation of Dol-PP-GlcNAc₂Man₉ and Dol-PP-GlcNAc₂Man₉Glc₁ in the endoplasmic reticulum of patients’ fibroblasts that can be detected by analyzing the lipid-linked oligosaccharyl intermediates. Five patients with CDG-Ih have been described so far. The clinical presentation of four of these patients was severe with death in early infancy. In this report, we describe two mildly affected siblings with CDG-Ih caused by two novel mutations.While one mutation (c.1434delC) causes a frame shift resulting in a premature termination codon (p.485X), the point mutation of the other allele (c.845C>T, p.A282V) causes an amino acid replacement in a highly conserved region of the hALG8 gene. The two siblings show similar symptoms, including pseudo-gynecomastia, epicanthus, muscular hypotonia, mental retardation and ataxia, expanding the genetic and clinical spectrum of CDG-Ih.     

Femtosecond dynamics of the DNA intercalator ethidium and electron transfer with mononucleotides in water

Ethidium (E) is a powerful probe of DNA dynamics and DNA-mediated electron transfer (ET). Molecular dynamical processes, such as solvation and orientation, are important on the time scale of ET. Here, we report studies of the femtosecond and picosecond time-resolved dynamics of E, E with 2′deoxyguanosine triphosphate (GTP) in water, and E with 7-deaza-2′-deoxyguanosine triphosphate (ZTP) in water; E undergoes ET with ZTP but not GTP. These studies elucidate the critical role of relative orientational motions of the donor–acceptor complex on ET processes in solution. For ET from ZTP to E, such motions are in fact the rate-determining step. Our results indicate that these complexes reorient before ET. The time scale for the solvation of E in water is 1 ps, and the orientational relaxation time of E is 70 ps. The impact of orientational and solvation effects on ET between E and mononucleotides must be considered in the application of E as a probe of DNA ET.