Rickettsia africae infection complicated with painful sacral syndrome in an Italian traveller returning from Zimbabwe

We report a case of Rickettsia africae infection complicated with painful sacral syndrome in an Italian traveller returning from Zimbabwe. The patient presented with fever, a tache noire on the left leg, and a neurological syndrome characterized by severe pain of the left leg, predominantly located in the left dorsal thigh and radiating to the calf; she had urinary retention and faecal incontinence. The diagnosis of R. africae was confirmed by polymerase chain reaction on a skin biopsy. The severe left leg pain persisted despite a complete course of doxycycline. A 4-month course of corticosteroids and the addition of carbamazepine was needed to achieve the control of pain. This case highlights the possibility of severe manifestations of R. africae infection and the possibility of a complex pathogenesis of the neurological syndrome, due perhaps to both the direct damage induced by R. africae and an immune-mediated mechanism

New chitosan nanobubbles for ultrasound-mediated gene delivery: preparation and in vitro characterization

BACKGROUND: The development of nonviral gene delivery systems is one of the most intriguing topics in nanomedicine. However, despite the advances made in recent years, several key issues remain unsettled. One of the main problems relates to the difficulty in designing nanodevices for targeted delivery of genes and other drugs to specific anatomic sites. In this study, we describe the development of a novel chitosan nanobubble-based gene delivery system for ultrasound-triggered release. METHODS AND RESULTS: Chitosan was selected for the nanobubble shell because of its low toxicity, low immunogenicity, and excellent biocompatibility, while the core consisted of perfluoropentane. DNA-loaded chitosan nanobubbles were formed with a mean diameter of less than 300 nm and a positive surface charge. Transmission electron microscopic analysis confirmed composition of the core-shell structure. The ability of the chitosan nanobubbles to complex with and protect DNA was confirmed by agarose gel assay. Chitosan nanobubbles were found to be stable following insonation (2.5 MHz) for up to 3 minutes at 37°C. DNA release was evaluated in vitro in both the presence and absence of ultrasound. The release of chitosan nanobubble-bound plasmid DNA occurred after just one minute of insonation. In vitro transfection experiments were performed by exposing adherent COS7 cells to ultrasound in the presence of different concentrations of plasmid DNA-loaded nanobubbles. In the absence of ultrasound, nanobubbles failed to trigger transfection at all concentrations tested. In contrast, 30 seconds of ultrasound promoted a moderate degree of transfection. Cell viability experiments demonstrated that neither ultrasound nor the nanobubbles affected cell viability under these experimental conditions. CONCLUSION: Based on these results, chitosan nanobubbles have the potential to be promising tools for ultrasound-mediated DNA delivery

Serological diagnosis of canine leishmaniosis: comparison of three commercial ELISA tests (Leiscan®, ID Screen® and Leishmania 96®), a rapid test (Speed Leish K®) and an in-house IFAT

BACKGROUND: Speed Leish K(®) is used as a serological screening test for Leishmania infection prior to vaccination. Limited comparative serological studies with Speed Leish K(®) have been performed. The aim of this study was to evaluate the diagnostic performance of four commercially available serologic tests including ELISAs (Leiscan(®), ID Screen(®) and Leishmania 96(®)), a rapid test (Speed Leish K(®)) and an in-house IFAT for the detection of specific antibodies against Leishmania infantum antigen in dogs in different states of infection. METHODS: Sick infected dogs (n = 36), healthy infected dogs (n = 18), L. infantum seropositive dogs with low to high levels of antibodies (n = 53), dogs seropositive to other pathogens (to evaluate cross reaction) (n = 14) and uninfected dogs from a non-endemic area (n = 50) and from an endemic area (n = 32) were analysed by the serological methods mentioned above. RESULTS: The sensitivity was as follows: ID Screen(®) (0.953), Leiscan(®) and Leishmania 96(®) (0.925), IFAT (0.869) and Speed Leish K(®) (0.636). The maximum specificity (1.000) was attained for all diagnostic tests except the Leishmania 96(®) (0.896) and IFAT (0.917). The accuracy was as follows: ID Screen(®) (0.975), Leiscan(®) (0.961), Leishmania 96(®) (0.911), IFAT (0.892) and Speed Leish K(®) (0.808). In relation to the area under the ROC curve (AUC-ROC), the maximum value was attained with the ID Screen(®) (0.993) closely followed by Leiscan(®) (0.990), then, Leishmania 96(®) (0.962), IFAT (0.926) and Speed Leish K(®) (0.818). For the Kappa index, the best result was obtained by the ID Screen(®) (0.951) followed by Leiscan(®) (0.921), Leishmania 96(®) (0.822), IFAT (0.783) and Speed Leish K(®) (0.622). Statistically significant differences were found between the AUC-ROC of quantitative serological tests and the only qualitative rapid test evaluated. There were also statistically significant differences between AUC-ROC of the ELISAs (ID Screen(®) and Leiscan(®)) and IFAT. CONCLUSIONS: Leiscan(®) and ID Screen(®) had superior diagnostic performance measures than IFAT and all quantitative serological tests were superior when compared to Speed Leish K(®). Thus, Speed Leish K(®) may be considered a less valuable screening test prior to vaccination as it may result in vaccination of seropositive dogs and in some cases seropositive sick dogs

Intrauterine parvovirus B19 infection: early prenatal diagnosis is possible

n/

Mitochondrial cytochrome b DNA sequence variations: an approach to fish species identification in processed fish products.

The identification of fish species in food products is problematic because morphological features of the fish are partially or completely lost during processing. It is important to determine fish origin because of the increasing international seafood trade and because European Community Regulation 104/2000 requires that the products be labeled correctly. Sequence analysis of PCR products from a conserved region of the cytochrome b gene was used to identity fish species belonging to the families Gadidae and Merluccidae in 18 different processed fish products. This method allowed the identification of fish species in all samples. Fish in all of the examined products belonged to these two families, with the exception of one sample of smoked baccalà (salt cod), which was not included in the Gadidae cluster

Entanglement swapping with photons generated on-demand by a quantum dot

Photonic entanglement swapping, the procedure of entangling photons without any direct interaction, is a fundamental test of quantum mechanics and an essential resource to the realization of quantum networks. Probabilistic sources of non-classical light can be used for entanglement swapping, but quantum communication technologies with device-independent functionalities demand for push-button operation that, in principle, can be implemented using single quantum emitters. This, however, turned out to be an extraordinary challenge due to the stringent requirements on the efficiency and purity of generation of entangled states. Here we tackle this challenge and show that pairs of polarization-entangled photons generated on-demand by a GaAs quantum dot can be used to successfully demonstrate all-photonic entanglement swapping. Moreover, we develop a theoretical model that provides quantitative insight on the critical figures of merit for the performance of the swapping procedure. This work shows that solid-state quantum emitters are mature for quantum networking and indicates a path for scaling up.Comment: The first four authors contributed equally to this work. 17 pages, 3 figure