No abstract

Cyclic nucleotide phosphodiesterase 3B (PDE3B) has been suggested to be critical for mediating insulin/ IGF-1 inhibition of cAMP signaling in adipocytes, liver, and pancreatic β cells. In Pde3b-KO adipocytes we found decreased adipocyte size, unchanged insulin-stimulated phosphorylation of protein kinase B and activation of glucose uptake, enhanced catecholamine-stimulated lipolysis and insulin-stimulated lipogenesis, and blocked insulin inhibition of catecholamine-stimulated lipolysis. Glucose, alone or in combination with glucagon-like peptide-1, increased insulin secretion more in isolated pancreatic KO islets, although islet size and morphology and immunoreactive insulin and glucagon levels were unchanged. The β 3 -adrenergic agonist CL 316,243 (CL) increased lipolysis and serum insulin more in KO mice, but blood glucose reduction was less in CL-treated KO mice. Insulin resistance was observed in KO mice, with liver an important site of alterations in insulin-sensitive glucose production. In KO mice, liver triglyceride and cAMP contents were increased, and the liver content and phosphorylation states of several insulin signaling, gluconeogenic, and inflammation-and stress-related components were altered. Thus, PDE3B may be important in regulating certain cAMP signaling pathways, including lipolysis, insulin-induced antilipolysis, and cAMP-mediated insulin secretion. Altered expression and/or regulation of PDE3B may contribute to metabolic dysregulation, including systemic insulin resistance.

A self-destroying, biodegradable, and polycationic polyester, poly(trans-4-hydroxy-l-proline ester) (PHP ester), was synthesized, and the interaction of the polymer with polyanion DNA was investigated. Degradation of the polymer in aqueous solution was investigated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and by measuring the pH change as carboxylic acids are formed as products of the degradation of the polymer backbone ester bond. It was shown from MALDI-MS data that the polymer degraded to less than half of the intact polymer molecular weight in less than 2 h. But a slower degradation rate after initial rapid degradation (within 1 day) was apparent. A self-destroying mechanism at the initial stage is proposed. The polymer was gradually degraded to near completion in 3 months in an aqueous solution to monomer, hydroxyproline, a major constituent of collagen, which could easily be detected by using MALDI-MS. Although the polymer degraded very quickly in an aqueous solution, it formed stable PHP ester/DNA complexes by electrostatic interaction when the polymer was mixed with the polyanionic DNA solution. The condensation behavior of DNA with the polymer to form self-assembled PHP ester/DNA complexes was characterized by electrophoretic mobility shift assay, dynamic light scattering, ζ potential, and nuclease resistance assay. These results show that PHP ester forms a strong complex with DNA by means of electrostatic interaction. Transfection of β-galactosidase gene into mammalian cell using PHP ester/DNA complexes was successful, showing the possibility of using PHP ester as a biodegradable gene delivery carrier.

PDE3A cyclic nucleotide phosphodiesterases regulate cAMP-and cGMP-mediated intracellular signaling in cardiac myocytes. We used antibodies to different regions of PDE3A to demonstrate the presence of three PDE3A isoforms in these cells. These isoforms, whose apparent molecular weights are 136,000, 118,000, and 94,000 ("PDE3A-136," "PDE3A-118," and "PDE3A-94"), are identical save for the deletion of different lengths of N-terminal sequence containing two membrane-association domains and sites for phosphorylation/activation by protein kinase B ("PK-B") and protein kinase A ("PK-A"). PDE3A-136 contains both membrane-association domains and the PK-B and PK-A sites. PDE3A-118 contains only the downstream membrane-association domain and the PK-A sites. PDE3A-94 lacks both membrane localization domains and the PK-B and PK-A sites. The three isoforms are translated from two mRNAs derived from the PDE3A1 gene: PDE3A-136 is translated from PDE3A1 mRNA, whereas PDE3A-118 and PDE3A-94 are translated from PDE3A2 mRNA. Experiments involving in vitro transcription/translation indicate that PDE3A-118 and PDE3A-94 may be translated from different AUGs in PDE3A2 mRNA. These findings suggest that alternative transcriptional and post-transcriptional processing of the PDE3A gene results in the generation of two mRNAs and three protein isoforms in cardiac myocytes that differ with respect to intracellular localization and may be regulated through different signaling pathways.

Background: Multicenter studies may be required for establishing guidelines for safe usage of iodinated contrast media (ICM).Purpose: To identify the prevalence, patterns, risk factors, and preventive measures for ICM-related hypersensitivity reactions (HSRs). Materials and Methods:Between March 2017 and October 2017, a total of 196 081 patients who underwent ICM administration were enrolled from seven participating institutions. The occurrence of HSRs and baseline patient information were recorded. x 2 and Student t test were performed, and logistic regression analyses were used to identify risk factors that predict occurrence and recurrence of HSR.Results: Among 196 081 patients (mean age 6 standard deviation, 59.1 years 6 16.0; 105 014 men and 91 067 women) who underwent ICM administration, the overall prevalence of HSRs was 0.73% (1433 of 196 081), and severe reactions occurred in 0.01% (17 of 196 081). Conditional logistic regression for patients with HSR (n = 1433) and a control group (1:1 matched group for age, sex, ICM product, and institution) demonstrated that a patient's previous individual history of an ICM-related HSR (adjusted odds ratio [OR], 198.8; P , .001), hyperthyroidism (adjusted OR, 3.6; P = .04), drug allergy (adjusted OR, 3.5; P , .001), and other allergic diseases (adjusted OR, 6.8; P , .001) and a family history of ICM-related HSRs (adjusted OR, 14.0; P = .01) were predictors of HSR occurrence. Logistic regression analysis showed that use of premedication with antihistamine (OR, 0.5; P = .01) and change in the generic profile of ICM (OR, 0.5; P , .001) were preventive against recurrent HSR. Conclusion:Family history as well as previous individual history of hypersensitivity reactions (HSRs) to iodinated contrast media (ICM) were risk factors for HSR occurrence, suggesting a potential genetic predisposition. A change in the culprit ICM and premedication with antihistamine are useful for reducing the recurrence of HSRs.

Methoxypoly(ethylene glycol)-block-poly(L-lysine) dendrimer was designed to form a water-soluble complex with plasmid DNA. The copolymer was synthesized by the liquid-phase peptide synthesis method. It was characterized by 1H NMR and matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrum. Agarose gel electrophoresis and DNase I protection assay proved that this linear polymer/dendrimer block copolymer assembled spontaneously with plasmid DNA, forming a water-soluble complex which increased the stability of the complexed DNA. Atomic force microscopy of the complex was evaluated at various charge ratios showing that the copolymer/DNA complex was like a globular shape.

To investigate the delivery of DNA into cells, lactose-poly(ethylene glycol)-grafted poly-L-lysine (Lac-PEG-PLL) polymers were synthesized as polymeric gene carriers. The new synthetic carriers, varying the substitution ratio of lactose-poly(ethylene glycol) (lactose-PEG), were characterized by NMR spectroscopy and size-exclusion chromatography. Electrophoretic mobility assay confirmed that the new gene carrier makes a complex with plasmid DNA. The attached poly(ethylene glycol) gives better solubility properties to gene/carrier complex. Transfection experiments showed that Lac-PEG-PLL efficiently delivers DNA to a hepatoma cell line in vitro; the best efficiency was achieved at a 1:3 weight ratio of DNA to carrier. As the lactose-PEG substitution content increased up to 30%, the transfection efficiency increased, which demonstrates that the lactose serves as a targeting moiety. No considerable cytotoxicity was observed due to Lac-PEG-PLL or its complex with DNA within the concentration range for this experiment. The use of chloroquine increased transfection efficiency that indicates the involvement of hydrolytic degradation of the system in lysosome. It is likely that plasmid DNA/Lac-PEG-PLL complexes enter the cells through a receptor-mediated endocytosis mechanism. These results show that Lac-PEG-PLL can form a complex with plasmid DNA and serve as an efficient gene delivery carrier with lower cytotoxicity compared to that of poly-L-lysine. Therefore, it is expected that our Lac-PEG-PLL carrier can be used as an in vivo gene delivery vector.

Our study demonstrated that switching monopolar RFA using the multichannel RF system at a 2- or 3-cm interprobe distance and at a 30-second switching time can create a large, confluent coagulation zone in the liver within a clinically acceptable time frame. We believe that this technology will provide a useful tool for the treatment of large liver tumors.