Nanoparticulate transport of oximes over an in vitro blood-brain barrier model

Background

Due to the use of organophosphates (OP) as pesticides and the availability of OP-type nerve agents, an effective medical treatment for OP poisonings is still a challenging problem. The acute toxicity of an OP poisoning is mainly due to the inhibition of acetylcholinesterase (AChE) in the peripheral and central nervous systems (CNS). This results in an increase in the synaptic concentration of the neurotransmitter acetylcholine, overstimulation of cholinergic receptors and disorder of numerous body functions up to death. The standard treatment of OP poisoning includes a combination of a muscarinic antagonist and an AChE reactivator (oxime). However, these oximes can not cross the blood-brain barrier (BBB) sufficiently. Therefore, new strategies are needed to transport oximes over the BBB.

Methodology/Principal Findings

In this study, we combined different oximes (obidoxime dichloride and two different HI 6 salts, HI 6 dichloride monohydrate and HI 6 dimethanesulfonate) with human serum albumin nanoparticles and could show an oxime transport over an in vitro BBB model. In general, the nanoparticulate transported oximes achieved a better reactivation of OP-inhibited AChE than free oximes.

Conclusions/Significance

With these nanoparticles, for the first time, a tool exists that could enable a transport of oximes over the BBB. This is very important for survival after severe OP intoxication. Therefore, these nanoparticulate formulations are promising formulations for the treatment of the peripheral and the CNS after OP poisoning.     

Detection of BrdUrd incorporation in mammalian chromosomes by a BrdUrd antibody

Summary A bromodeoxyuridine antibody staining technique (BAT) was applied for the analysis of human chromosomes of different chromosomal band resolution. For this purpose lymphocyte cultures were synchronized and labeled with bromodeoxyuridine during the second half of the S-phase. Generally BAT was found comparable to GTG banding though some prominent GTG bands and the constitutive heterochromatin exhibit less intense staining with this technique.     

Structural comparison between oxidized and reduced Escherichia coli thioredoxin. Proton NMR and CD studies

Escherichia coli thioredoxin (Mr 11,700) usually functions as a hydrogen carrier protein that undergoes reversible oxidation/reduction reactions of its active-site disulfide linkage. By use of a number of assigned and identified resonances in one- and two-dimensional 1H NMR spectra, the two forms of the protein have been compared. Only groups that are relatively close to the active-site Cys-32, Cys-35 linkage such as Trp-28, Trp-31, Phe-27, Ala-29, and Val-25 undergo substantial changes in their 1H NMR chemical shift upon reduction. Various residues that are further removed from the active site, like Tyr-49, Tyr-70, His-6, Phe-12, Phe-81, and Phe-102, appear to be little affected (less than 0.02 ppm) by the reduction, suggesting that the rest of the protein structure is not much affected. Thus, the structural changes that occur upon reduction appear to be localized to the disulfide-containing turn and the central strand of the twisted beta-sheet that directly leads to this turn. Notwithstanding the apparent similarity in the secondary and tertiary structures of the oxidized and reduced forms of the protein, the thermal stability of the protein decreases by 10 degrees C upon the reduction of the single disulfide. This was found by both 1H NMR and near- and far-ultraviolet circular dichroism studies. Oxidized thioredoxin was also more resistant to alkaline denaturation. Furthermore, the exchange rate of the relatively stable slow-exchanging backbone amide protons that are part of the core of the twisted five-stranded beta-sheet of thioredoxin increases substantially after reduction.(ABSTRACT TRUNCATED AT 250 WORDS)     

No corpora sesamoidea laryngis in man and animal]

The fact that the Corpora sesamoidea have never been precisely defined has led to a series of small cartilaginous bodies in the larynx being thus designated, for want of a better solution. Since the corpora sesamoidea have been identified as capsular bodies, however, originating in or in connection with a synovial capsule, there remained only one laryngeal cartilage which appeared to fulfill all the criteria of sesamoid cartilage, namely the papilionaceous cartilage found in all alar species from Monotremata to Carnivora, and which comparative anatomists term proarytaenoid cartilage. If Goeppert's findings are regarded as having an additional functional significance, then it is clear that this cartilage too, like cartilagines interarytaenoidea, postarytaenoidea (dorsoarytaenoidea in the dog?) pararytaenoidea, cunciformis, corniculata, intercorniculata and triticea, is a connecting cartilage.     

Cryo‐Immunoelectron Microscopy of Adherent Cells Improved by the Use of Electrospun Cell Culture Substrates

Electrospun nanofibres are an excellent cell culture substrate, enabling the fast and non‐disruptive harvest and transfer of adherent cells for microscopical and biochemical analyses. Metabolic activity and cellular structures are maintained during the only half a minute‐long harvest and transfer process. We show here that such samples can be optimally processed by means of cryofixation combined either with freeze‐substitution, sample rehydration and cryosection‐immunolabelling or with freeze‐fracture replica‐immunolabelling. Moreover, electrospun fibre substrates are equally suitable for complementary approaches, such as biochemistry, fluorescence microscopy and cytochemistry.