Preliminary study of organochlorine residues in human milk and cord blood

A large collection of human milk samples and cord blood from various hospitals of Tunis is studied for organochlorine residues. Some results obtained by ECD-GC are given.     

Aging exacerbates damage and delays repair of alveolar epithelia following influenza viral pneumonia

Background

Influenza virus infection causes significantly higher levels of morbidity and mortality in the elderly. Studies have shown that impaired immunity in the elderly contributes to the increased susceptibility to influenza virus infection, however, how aging affects the lung tissue damage and repair has not been completely elucidated.

Methods

Aged (16–18 months old) and young (2–3 months old) mice were infected with influenza virus intratracheally. Body weight and mortality were monitored. Different days after infection, lung sections were stained to estimate the overall lung tissue damage and for club cells, pro-SPC⁺ bronchiolar epithelial cells, alveolar type I and II cells to quantify their frequencies using automated image analysis algorithms.

Results

Following influenza infection, aged mice lose more weight and die from otherwise sub-lethal influenza infection in young mice. Although there is no difference in damage and regeneration of club cells between the young and the aged mice, damage to alveolar type I and II cells (AT1s and AT2s) is exacerbated, and regeneration of AT2s and their precursors (pro-SPC-positive bronchiolar epithelial cells) is significantly delayed in the aged mice. We further show that oseltamivir treatment reduces virus load and lung damage, and promotes pulmonary recovery from infection in the aged mice.

Conclusions

These findings show that aging increases susceptibility of the distal lung epithelium to influenza infection and delays the emergence of pro-SPC positive progenitor cells during the repair process. Our findings also shed light on possible approaches to enhance the clinical management of severe influenza pneumonia in the elderly.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-014-0116-z) contains supplementary material, which is available to authorized users.     

Conjugation of chelating agents to proteins and radiolabeling with trivalent metallic isotopes

Peptides and proteins may be tagged with metallic elements in order to use them as imaging reporters or for other applications. The polypeptide of interest is first conjugated to a suitable chelating agent that forms stable complexes with the element of interest. This conjugation step is undertaken either in aqueous or in non-aqueous conditions depending on the solubility of the substrate. For polypeptides of greater than approximately 10 kDa in size, this is normally done in aqueous medium. Most commonly the chelators are reacted with lysine amino groups. The protein is first desalted into a suitable buffer at pH 8-9 and a molar excess of a bifunctional chelating agent is added. After a suitable period of incubation, excess, unreacted or hydrolyzed chelator is removed and the protein conjugate is desalted into an acidic buffer. The conjugate can then be tagged by addition of a suitable metal salt followed, if necessary, by removal of unchelated metal. As described in the protocol that follows, the entire conjugation, purification and labeling procedure takes about 2 d.     

Myocardial transfection with naked DNA plasmid encoding hepatocyte growth factor prevents the progression of heart failure in dogs

This study examined the effects of localized intramyocardial injections of hepatocyte growth factor (HGF) naked DNA plasmid on the progression of left ventricular (LV) dysfunction and remodeling in dogs with moderate heart failure (HF). Twenty-one dogs with intracoronary microembolization-induced HF [LV ejection fraction (EF) = 35-40%] were randomized into three treatment groups, namely, high-dose HGF plasmid (4.0 mg, n = 7), low-dose HGF plasmid (0.4 mg, n = 7), and sham-operated controls treated with normal saline (n = 7). A total of 10-15 injections of HGF plasmid or saline were made directly into the anterior wall of LV. LV EF and end-systolic volume (ESV) were measured before randomization (pretreatment) and at the end of 3 mo of follow-up (posttreatment). Treatment effect (Δ) was calculated as the change from pre- to posttreatment. Protein expression of sarcoplasmic reticulum (SR) Ca(2+)-cycling proteins was determined in LV tissue obtained from the sites of HGF injection and remote areas. Low-dose HGF attenuated the decline in EF (ΔEF: -3 ± 1 vs. -8 ± 1%, P < 0.05) and the increase in ESV (ΔESV: 6 ± 2 vs. 10 ± 1 ml, P < 0.05) seen in control sham-operated dogs, whereas high-dose HGF significantly increased EF (ΔEF: 4 ± 1 vs. -8 ± 1%, P < 0.05) and prevented the increase in ΔESV (ESV: -1 ± 1 vs. 10 ± 1 ml, P < 0.05) compared with control dogs. Treatment with high- and low-dose HGF improved the expression of the SR Ca(2+)-cycling proteins compared with controls. In conclusion, regional intramyocardial injections of HGF naked DNA plasmid improve regional and global LV function and prevent progressive LV remodeling.     

Underwater linear polarization: physical limitations to biological functions

Polarization sensitivity is documented in a range of marine animals. The variety of tasks for which animals can use this sensitivity, and the range over which they do so, are confined by the visual systems of these animals and by the propagation of the polarization information in the aquatic environment. We examine the environmental physical constraints in an attempt to reveal the depth, range and other limitations to the use of polarization sensitivity by marine animals. In clear oceanic waters, navigation that is based on the polarization pattern of the sky appears to be limited to shallow waters, while solar-based navigation is possible down to 200-400 m. When combined with intensity difference, polarization sensitivity allows an increase in target detection range by 70-80% with an upper limit of 15 m for large-eyed animals. This distance will be significantly smaller for small animals, such as plankton, and in turbid waters. Polarization-contrast detection, which is relevant to object detection and communication, is strongly affected by water conditions and in clear waters its range limit may reach 15 m as well. We show that polarization sensitivity may also serve for target distance estimation, when examining point source bioluminescent objects in the photic mesopelagic depth range.     

Application of transgenic plants in understanding responses to atmospheric change

Acclimation of plants to an increase in atmospheric carbon dioxide concentration is a well described phenomenon. It is characterized by an increase in leaf carbohydrates and a degradation of ribulose 1, 5-bisphosphate carboxylase protein (Rubisco) leading in the long term to a lower rate of CO₂ assimilation than expected from the kinetic constants of Rubisco. This article summarizes studies with transgenic plants grown in elevated pCO₂ which are modified in their capacity of CO₂ fixation, of sucrose and starch synthesis, of triosephosphate and sucrose transport and of sink metabolism of sucrose. These studies show that a feedback accumulation of carbohydrates in leaves play only a minor role in acclimation, because leaf starch synthesis functions as an efficient buffer for photoassimilates. There is some evidence that in elevated pCO₂, plants grow faster and senescence is induced earlier.     

Companion cell-specific inhibition of the potato sucrose transporter SUT1

In many plants, translocation of sucrose from mesnsophyll to phloem for long-distance transport is carrier-mediated. The sucrose H⁺-symporter gene SUT1 from potato is expressed at high levels in the phloem of mature, exporting leaves and at lower levels in other organs. Inhibition of SUT1 by expression of an antisense gene in companion cells under control of the rolC promoter leads to accumulation of high amounts of soluble and insoluble carbohydrates in leaves and inhibition of photosynthesis. The distribution of in situ localized starch does not correspond with areas of reduced photosynthesis as shown by fluorescence imaging. Dissection of antisense effects on sink and source organs by reciprocal grafts shows that inhibition of transporter gene expression in leaves is sufficient to produce chlorosis in leaves and reduced tuber yield. In contrast to the arrest of plasmodesmal development found in plants that express yeast invertase in the apoplast, in mature leaves of sucrose transporter antisense plants plasmodesmata are branched and have median cavities. These data strongly support an apoplastic mode of phloem loading in potato, in which the sucrose transporter located at the plasma membrane of the sieve element/companion cell complex represents the primary route for sugar uptake into the long-distance translocation pathway.     

The relationship between running speed and measures of vertical jump in professional basketball players: a field-test approach

The purpose of this study was to examine the relationship between vertical jump measures and sprint speed over 10, 20, and 40 m in professional basketball players. Thirty-three professional basketball players aged (±SD) (27.4 ± 3.3 years), body mass (89.8 ± 11.1 kg), and stature (192 ± 8.2 cm) volunteered to participate in this study. All participants were tested on squat jump, countermovement jump, and 40-m running speed. The results show that all jump measures in absolute terms were correlated significantly to running performance over 10-, 20-, and 40-m sprint times. None of the jumping performance peak powers and reactive strength were found to have a correlation to running speed times in absolute term. Furthermore, all jump height measures relative to body mass except reactive strength had a marked and significant relationship with all sprint performance times. The results of this study indicate that while there is a strong and marked relationship between 10-, 20-, and 40-m sprint, there is also a considerable variation within the factors that contribute to performance over these distances. This may indicate that, separate training strategies could be implemented to improve running speed over these distances.     

Synthesis and biological evaluation of new N-acyl-homoserine-lactone analogues, based on triazole and tetrazole scaffolds, acting as LuxR-dependent quorum sensing modulators

New analogues of N-acyl-homoserine-lactone (AHL), in which the amide was replaced by a triazole or tetrazole ring, were prepared and tested for their activity as LuxR-dependent QS modulators. Several compounds showed a level of antagonistic or agonistic activity, notably some 1,4-triazolic and 1,5-tetrazolic derivatives, whereas the 2,5-tetrazolic compounds were inactive. In 1,5-tetrazoles, substituted with butyrolactone and an alkyl chain, the activity was reversed, depending on the connection between the lactone and the tetrazole. The C-N connected compounds were agonists whereas the C-C connected ones were antagonists.