Phosphatidylinositol 4,5-bisphosphate stimulates alveolar epithelial fluid clearance in male and female adult rats

Cell membrane phospholipids, like phosphatidylinositol 4,5-bisphosphate [PI(4,5)P(2)], can regulate epithelial Na channel (ENaC) activity. Gender differences in lung ENaC expression have also been demonstrated. However, the effects in vivo on alveolar fluid clearance are uncertain. Thus PI(4,5)P(2) effects on alveolar fluid clearance were studied in male and female rats. An isosmolar 5% albumin solution was intrapulmonary instilled; alveolar fluid clearance was studied for 1 h. Female rats had a 37 ± 19% higher baseline alveolar fluid clearance than male rats. Bilateral ovariectomy attenuated this gender difference. Compared with controls, PI(4,5)P(2) instillation (300 μM) increased alveolar fluid clearance by ～93% in both genders. Amiloride or the specific αENaC small-interfering RNA inhibited baseline and PI(4,5)P(2)-stimulated alveolar fluid clearance in both genders, indicating a dependence on amiloride-sensitive pathways. The fraction of amiloride inhibition was greater in PI(4,5)P(2)-instilled rats (male: 64 ± 10%; female: 70 ± 11%) than in controls (male: 30 ± 6%; female: 44 ± 8%). PI(4,5)P(2) instillation lacked additional alveolar fluid clearance stimulation above that of terbutaline, nor did propranolol inhibit alveolar fluid clearance after PI(4,5)P(2) instillation, indicating that PI(4,5)P(2) stimulation was not secondary to endogenous β-adrenoceptor activation. PI(4,5)P(2) amine instillation resulted in an intermediate alveolar fluid clearance stimulation, suggesting that, to reach maximal alveolar fluid clearance stimulation, PI(4,5)P(2) must reside in cell membranes. In summary, PI(4,5)P(2) instillation upregulated in vivo alveolar fluid clearance similar to short-term β-adrenoceptor upregulation of alveolar fluid clearance. PI(4,5)P(2) stimulation was mediated partly by increased amiloride-sensitive Na transport. There exist important gender-related effects suggesting a female advantage that may have clinical implications for resolution of acute lung injury.     

Microtubule-associated proteins MAP65-1 and MAP65-2 positively regulate axial cell growth in etiolated Arabidopsis hypocotyls

The Arabidopsis thaliana MAP65-1 and MAP65-2 genes are members of the larger eukaryotic MAP65/ASE1/PRC gene family of microtubule-associated proteins. We created fluorescent protein fusions driven by native promoters that colocalized MAP65-1 and MAP65-2 to a subset of interphase microtubule bundles in all epidermal hypocotyl cells. MAP65-1 and MAP65-2 labeling was highly dynamic within microtubule bundles, showing episodes of linear extension and retraction coincident with microtubule growth and shortening. Dynamic colocalization of MAP65-1/2 with polymerizing microtubules provides in vivo evidence that plant cortical microtubules bundle through a microtubule-microtubule templating mechanism. Analysis of etiolated hypocotyl length in map65-1 and map65-2 mutants revealed a critical role for MAP65-2 in modulating axial cell growth. Double map65-1 map65-2 mutants showed significant growth retardation with no obvious cell swelling, twisting, or morphological defects. Surprisingly, interphase microtubules formed coaligned arrays transverse to the plant growth axis in dark-grown and GA(4)-treated light-grown map65-1 map65-2 mutant plants. We conclude that MAP65-1 and MAP65-2 play a critical role in the microtubule-dependent mechanism for specifying axial cell growth in the expanding hypocotyl, independent of any mechanical role in microtubule array organization.     

Drug safety of rosiglitazone and pioglitazone in France: a study using the French PharmacoVigilance database

Background

Spontaneous reporting of adverse drug reactions (ADRs) is an important method for pharmacovigilance, but under-reporting and poor quality of reports are major limitations. The aim of this study was to evaluate if repeated one-page ADR information letters affect (i) the reporting rate of ADRs and (ii) the quality of the ADR reports.

Methods

All 151 primary healthcare units in the Region Västra Götaland, Sweden, were randomly allocated (1:1) to an intervention (n = 77) or a control group (n = 74). The intervention consisted of one-page ADR information letters administered at three occasions during 2008 to all physicians and nurses in the intervention units. The number of ADR reports received from the 151 units was registered, as was the quality of the reports, which was defined as high if the ADR was to be reported according to Swedish regulations, that is, if the ADR was (i) serious, (ii) unexpected, and/or (iii) related to the use of new drugs and not labelled as common in the Summary of Product Characteristics. A questionnaire was administered to evaluate if the ADR information letter had reached the intended recipient.

Results

Before the intervention, no significant differences in reporting rate or number of high quality reports could be detected between the randomization groups. In 2008, 79 reports were sent from 37 intervention units and 52 reports from 30 control units (mean number of reports per unit ± standard deviation: 1.0 ± 2.5 vs. 0.7 ± 1.2, P = 0.34). The number of high quality reports was higher in intervention units than in control units (37 vs. 15 reports, 0.5 ± 0.9 vs. 0.2 ± 0.6, P = 0.048). According to the returned questionnaires (n = 1,292, response rate 57%), more persons in the intervention than in the control group had received (29% vs. 19%, P < 0.0001) and read (31% vs. 26%, P < 0.0001) an ADR information letter.

Conclusions

This study suggests that repeated ADR information letters to physicians and nurses do not increase the ADR reporting rate, but may increase the number of high quality reports.     

Host migration impacts on the phylogeography of Lyme Borreliosis spirochaete species in Europe

The geographic patterns of transmission opportunities of vector‐borne zoonoses are determined by a complex interplay between the migration patterns of the host and the vector. Here we examine the impact of host migration on the spread of a tick‐borne zoonotic disease, using Lyme Borreliosis (LB) spirochaetal species in Europe. We demonstrate that the migration of the LB species is dependent on and limited by the migration of their respective hosts. We note that populations of Borrelia spp. associated with birds (Borrelia garinii and B. valaisiana) show limited geographic structuring between countries compared with those associated with small mammals (Borrelia afzelii), and we argue that this can be explained by higher rates of migration in avian hosts. We also show the presence of B. afzelii strains in England and, through the use of the multi‐locus sequence analysis scheme, reveal that the strains are highly structured. This pattern in English sites is very different from that observed at the continental sites, and we propose that these may be recent introductions.     

Proteomic analysis of 3T3-L1 adipocyte mitochondria during differentiation and enlargement

The increase in adipose tissue mass arises in part from progressive lipid loading and triglyceride accumulation in adipocytes. Enlarged adipocytes produce the highest levels of pro-inflammatory molecules and reactive oxygen species (ROS). Since mitochondria are the site for major metabolic processes (e.g., TCA cycle) that govern the extent of triglyceride accumulation as well as the primary site of ROS generation, we quantitatively investigated changes in the adipocyte mitochondrial proteome during different stages of differentiation and enlargement. Mitochondrial proteins from 3T3-L1 adipocytes at different stages of lipid accumulation (days 0-18) were digested and labeled using the iTRAQ 8-plex kit. The labeled peptides were fractionated using a liquid phase isoelectric fractionation system (MSWIFT) to increase the depth of proteome coverage and analyzed using LC-MS/MS. A total of 631 proteins in the mitochondrial fraction, including endoplasmic reticulum-associated and golgi-related mitochondrial proteins, were identified and classified into 12 functional categories. A total of 123 proteins demonstrated a statistically significant change in expression in at least one of the time points over the course of the experiment. The identified proteins included enzymes and transporters involved in the TCA cycle, fatty acid oxidation, and ATP synthesis. Our results indicate that cultured adipocytes enter a state of metabolic-overdrive where increased flux through the TCA cycle and increased fatty acid oxidation occur simultaneously. The proteomic data also suggest that accumulation of reduced electron carriers and the resultant oxidative stress may be attractive targets for modulating adipocyte function in metabolic disorders.     

Functionalized, biocompatible coating for superparamagnetic nanoparticles by controlled polymerization of a thioglycosidic monomer

It is demonstrated that water-soluble, glucosylated poly(pentafluorostyrene) derivatives revealed favorable coating material properties for magnetic iron oxide nanoparticles. To prepare the coating material in high reproducibility and purity as well as in sufficient amounts, a new route of synthesis is established. The preparation and characterization of the glucosylated, tetrafluorostyryl monomer, by thiol-para-fluorine "click" reaction, and its polymerization, via nitroxide-mediated radical process, is presented in detail. In addition, the coating material and the resulting particle properties are investigated by means of XPS, DLS, TGA, TEM, and cryo-TEM as well as flow cytometry. The glycopolymer acts as an appropriate stabilizing agent for the superparamagnetic nanoparticles by the formation of an approximately 10 nm thick shell, as shown by the XPS analysis. Furthermore, the application of FITC-labeled glycopolymer yielded fluorescent, superparamagnetic nanoparticles, which can be used for monitoring cell-carbohydrate interactions, because these particles show no cytotoxicity toward 3T3 fibroblasts.