Lipid‐Bilayer Permeation of Drug‐Like Compounds

Lipid‐bilayer permeation is determinant for the disposition of xenobiotics in the body. It controls the pharmacokinetic behavior of drugs and is, in many cases, a prerequisite for intracellular targeting. Permeation of in vivo barriers is in general predicted from lipophilicity and related parameters. This article goes beyond the empirical correlations, and elucidates the processes and their interplay determining bilayer permeation. A flip‐flop model for bilayer permeation, which considers the partitioning rate constants beside the translocation rate constants, is compared with the diffusion model based on Fick's first law. According to the flip‐flop model, the ratios of aqueous volumes to barrier area can determine whether partitioning or translocation is rate‐limiting. The flip‐flop model allows permeation of anions and cations, and expands our understanding of pH‐dependent permeation kinetics. Some experimental evidences for ion‐controlled permeation at pH 7 are also included in this work.     

<Emphasis Type="Italic">Drosophila</Emphasis><Emphasis Type="Italic">P</Emphasis> transposons of the urochordata <Emphasis Type="Italic">Ciona intestinalis</Emphasis>

P transposons belong to the eukaryotic DNA transposons, which are transposed by a cut and paste mechanism using a P-element-coded transposase. They have been detected in Drosophila, and reside as single copies and stable homologous sequences in many vertebrate species. We present the P elements Pcin1, Pcin2 and Pcin3 from Ciona intestinalis, a species of the most primitive chordates, and compare them with those from Ciona savignyi. They showed typical DNA transposon structures, namely terminal inverted repeats and target site duplications. The coding region of Pcin1 consisted of 13 small exons that could be translated into a P-transposon-homologous protein. C. intestinalis and C. savignyi displayed nearly the same phenotype. However, their P elements were highly divergent and the assumed P transposase from C. intestinalis was more closely related to the transposase from Drosophila melanogaster than to the transposase of C. savignyi. The present study showed that P elements with typical features of transposable DNA elements may be found already at the base of the chordate lineage. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

THE EXPRESSION OF APELIN AND ITS RECEPTOR APJ DURING DIFFERENT PHYSIOLOGICAL STAGES IN THE BOVINE OVARY

Recent studies implicate that apelin and its receptor APJ may have important role for the modulation of angiogenesis. The aim of this study was to further characterise the regulation of apelin/APJ system in bovine ovary. Experiment 1: corpora lutea (CL) were assigned to the following stages: days 1-2, 3-4, 5-7, 8-12, 13-16, >18 (after regression) of oestrous cycle and of gravidity (month <3, 3-5, 6-7 and >8). Experiment 2: Follicles during maturation were divided into granulosa cells (GC) and theca interna (TI) and were examined separately. Classification of follicles occurred by follicle size and oestradiol-17β (E2) concentration in the follicular fluid (FF) (<0.5 ng/ml, 0.5-5 ng/ml; 5-40 ng/ml; 40-180 ng/ml; >180 ng/ml). Real-time RT-PCR (qPCR) was applied to investigate mRNA expression of examined factors. In general, the expression level of apelin during the oestrous cycle was significantly higher compared to the one during pregnancy. Apelin mRNA levels were always high during the cycle with a tendency of decrease after CL regression. The APJ mRNA in the CL was significantly up regulated on days 5-7 and 8-12 followed by a decrease on days 13-16, and further on days >18. The expression of APJ does not show any significant regulation in the CL throughout pregnancy. The expression of apelin and APJ was not statistically regulated in GC, but was significantly up regulated in follicles with an E2 concentration of more than 5 ng/ml and showed an increase according to growth and maturation of follicles. In conclusion, our data suggest that apelin/APJ system is involved in the mechanism regulating angiogenesis during follicle maturation as well as during CL formation and function in the bovine ovary.     

Comparison of exhaled breath condensate pH using two commercially available devices in healthy controls,asthma and COPD patients

Background

Analysis of exhaled breath condensate (EBC) is a non-invasive method for studying the acidity (pH) of airway secretions in patients with inflammatory lung diseases.

Aim

To assess the reproducibility of EBC pH for two commercially available devices (portable RTube and non-portable ECoScreen) in healthy controls, patients with asthma or COPD, and subjects suffering from an acute cold with lower-airway symptoms. In addition, we assessed the repeatability in healthy controls.

Methods

EBC was collected from 40 subjects (n = 10 in each of the above groups) using RTube and ECoScreen. EBC was collected from controls on two separate occasions within 5 days. pH in EBC was assessed after degasification with argon for 20 min.

Results

In controls, pH-measurements in EBC collected by RTube or ECoScreen showed no significant difference between devices (p = 0.754) or between days (repeatability coefficient RTube: 0.47; ECoScreen: 0.42) of collection. A comparison between EBC pH collected by the two devices in asthma, COPD and cold patients also showed good reproducibility. No differences in pH values were observed between controls (mean pH 8.27; RTube) and patients with COPD (pH 7.97) or asthma (pH 8.20), but lower values were found using both devices in patients with a cold (pH 7.56; RTube, p < 0.01; ECoScreen, p < 0.05).

Conclusion

We conclude that pH measurements in EBC collected by RTube and ECoScreen are repeatable and reproducible in healthy controls, and are reproducible and comparable in healthy controls, COPD and asthma patients, and subjects with a common cold.     

Effect of a proprietary protein supplement on recovery indices following resistance exercise in strength/power athletes

The effect of 42 g of protein ingested pre- and post-exercise on recovery from an acute resistance exercise session was examined in 15 male strength/power athletes who were randomly divided into a supplement (SUP) or placebo (PL) group. Subjects reported to the Human Performance Laboratory (HPL) on four separate occasions (T1–T4). Maximal strength [one repetition-maximum (1-RM)] testing was performed during T1. During T2 subjects performed four sets of ten repetitions at 80% of their 1-RM in the squat, dead lift and barbell lunge exercises with 90 s of rest between each set. Blood draws occurred at baseline (BL), immediate and 15 min post-exercise to determine testosterone, cortisol and creatine kinase (CK) concentrations. Subjects reported back to the HPL 24 (T3) and 48 h (T4) post-exercise for a BL blood draw and to perform four sets of ten repetitions with 80% of 1-RM for the squat exercise only. No differences in the number of repetitions performed in the squat exercise were seen between the groups at T2. Relative to T2, PL performed significantly (P < 0.05) fewer repetitions than SUP at T3 and T4 (−9.5 ± 5.5 repetitions vs. −3.3 ± 3.6 during T3, respectively, and −10.5 ± 8.2 repetitions vs. −2.3 ± 2.9 repetitions during T4, respectively). No differences in hormonal measures were seen between the groups. CK concentrations were significantly (P < 0.05) elevated at T3 for both groups, but continued to elevate (P < 0.05) at T4 for PL only. No significant group differences were noted for CK at any time point. Results indicate that a proprietary protein SUP consumed before and after a resistance training session significantly contributes to improvements in exercise recovery 24 and 48 h post-exercise.     

Recovery techniques for waterlogged archaeological sediments: a comparison of different treatment methods for samples from Neolithic lake shore settlements

This paper presents the first comparable overview of different recovery techniques used for waterlogged Neolithic sediments in the surroundings of the Alps in the last decades. Such an investigation became necessary because it was not known which parts of plants and types of remains were absent or completely underrepresented due to inappropriate recovery techniques in Slovenian archaeobotany up to 2006. During the 2007 excavation of the approximately 5,200 years old Neolithic pile dwelling site of Stare gmajne, Ljubljansko barje, Slovenia, we compared three methods for the investigation of botanical macroremains: method 1 (M1) included rough wet-sieving and subsequent drying of the fractions; method 2 (M2) rough wet sieving and keeping the fractions wet; and method 3 (M3) washing over and keeping the fractions wet. M3 with gentle washing, systematic subsampling, examination, and sorting of macroremains while wet, as well as using 0.355 mm as the smallest sieve mesh size gave the best results. When using the cruder M2 or M1 methods, waterlogged uncarbonized seeds of taxa such as Linum usitatissimum, Papaver somniferum and Brassica rapa, waterlogged chaff of Cerealia and pericarps of Maloideae and Quercus sp., which are all fragile, were underrepresented or even completely absent and therefore the plant spectra were strongly biased. On the contrary, taxa with lignified seed/fruit walls like Cornus mas, Corylus avellana or Rubus sp. were overrepresented when using the M2 and particularly the M1 method. The application of the M3, instead of the M1 method which has been traditionally used in Slovenian archaeobotany, helped us to identify uncarbonized remains of Linum usitatissimum and various species of Triticum for the first time in a waterlogged Neolithic site in Slovenia. Our study should contribute to a standardization of methods, which is desperately needed in archaeobotany. The study clearly shows that the plant spectra can be strongly biased if inappropriate handling techniques are used. The conclusions hold for all kinds of waterlogged sediments of different periods.     

Remote sensing of physiological data: Impact of long term captivity on body temperature variation of the feral cat (Felis catus) in Australia,recorded via Thermochron iButtons

This study reports body temperature regulation (T_b) and circadian rhythms of undisturbed feral cats in their natural environment in Australia over a continuous period of three months. It furthermore compares these data with T_b data collected of feral cats, after a period of one year in captivity. In free-ranging, undisturbed feral cats, a distinct robust, regular circadian rhythm (strength of rhythm) (21–59.8%) with higher body temperature in the dark (active) phase (mean±STD: 39.2±0.27 °C) and significantly lower body temperature during the light (rest) phase (mean±STD: 38.1±0.47 °C, P<0.001) was found. The acrophase (time of the daily peak) of the three free-ranging cats investigated varied from 22:34 h (LG 2), 22:57 h (LG 1) to 23:17 h (LG 3). In the course of captivity, the cats’ circadian rhythms shifted from nocturnality to a diurnal tendency, with an acrophase ranging from 12:00 h (MtK 2), 12:23 h (MtK 1) to 16:25 h (MtK 3). This change in rhythmicity was accompanied by a significant decrease in robustness (1.7–5.2%) and mean body temperature levels (37.77±0.34 °C) as well as minima and maxima (36–39 °C versus 35.5–41.9 °C, free-ranging cats) of three captive cats, resulting in a significant shift towards a decrease in amplitude.