Post-mortem investigations on a leatherback turtle Dermochelys coriacea stranded along the Northern Adriatic coastline

Leatherback sea turtles Dermochelys coriacea are regularly reported in the Mediterranean Sea but rarely reach the northern Adriatic Sea. In the summer of 2009, a well-preserved carcass of an adult female of this species was found dead along the coast of Lido di Venezia. A complete necropsy was carried out, along with evaluation of levels of tissue trace elements. The the post-mortem revealed acute severe bacterial gastroenteritis caused by Photobacterium damselae ssp. piscicida, an opportunistic agent that infected an apparently debilitated animal weakened by ingested plastic debris. High levels of heavy metals (Hg, Pb, Cd and As) found in the liver and kidneys might have contributed to the animal's demise. These findings support previous indications that marine debris is one of the major threats to marine animals, particularly for critically endangered species such as the leatherback turtle.     

Detection of benzo(a)pyrene photodegradation products using DNA electrochemical sensors

The reactivity of photodegradation products of benzo(a)pyrene vs. DNA has been assessed using both genomic and oligonucleotide based DNA electrochemical sensors. The kinetic of a photooxidation reaction of benzo(a)pyrene (BaP) carried out in controlled conditions using a 6 W UV lamp peaked at 365 nm has been studied using LC with fluorimetric detection. Degradation of benzo(a)pyrene by both UV and UV/H(2)O(2) exhibited pseudo-first-order reaction kinetics with half-lives ranging from 3.0 to 9.8h depending on the pH and on the amount of H(2)O(2). The oxidation products of benzo(a)pyrene obtained in different conditions were tested on genomic ssDNA electrochemical sensors obtained via immobilisation of salmon testis ss-DNA on graphite screen-printed electrodes. Guanines oxidation signals obtained using chronopotentiometry were used to detect the interaction of the products with DNA. The dose-response curve obtained with benzo(a)pyrene incubated 24 h at pH 4.7 was different from that of the parent compound indicating a different type of interaction with DNA. A DNA hybridisation sensor was also assembled using a thiolated/biotynilated 24-mer oligonucleotide immobilised on a gold screen-printed electrode and avidin-alkaline phosphatase conjugate. A voltammetric detection of naphtol was used to detect the hybridisation reaction. A net inhibition of the hybridisation reaction was observed after incubation with benzo(a)pyrene oxidation products that was attributed to the formation of stable adducts with the guanines of the biotinylated strand. LC-MS-MS studies of the oxidation products confirmed the presence of chemical species potentially forming adducts with DNA. The data reported demonstrate that DNA electrochemical sensors have the potential to be used to monitor remediation processes and to assess the potential toxicity vs. DNA of chemicals forming stable DNA adducts.     

Anti-GM1/GD1a complex antibodies in GBS sera specifically recognize the hybrid dimer GM1-GD1a

It is now emerging the new concept that the antibodies from some patients with Guillain-Barré syndrome (GBS) recognize an antigenic epitope formed by two different gangliosides, a ganglioside complex (GSC). We prepared the dimeric GM1-GD1a hybrid ganglioside derivative that contains two structurally different oligosaccharide chains to mimic the GSC. We use this compound to analyze sera from GBS patients by high-performance thin-layer chromatography immunostaining and enzyme-linked immunosorbent assay. We also synthesized the dimeric GM1-GM1 and GD1a-GD1a compounds that were used in control experiments together with natural gangliosides. The hybrid dimeric GM1-GD1a was specifically recognized by human sera from GBS patients that developed anti-oligosaccharide antibodies specific for grouped complex oligosaccharides, confirming the information that GBS patients developed antibodies against a GSC. High-resolution (1)H-(13)C heteronuclear single-quantum coherence-nuclear overhauser effect spectroscopy nuclear magnetic resonance experiments showed an interaction between the IV Gal-H1 of GM1 and the IV Gal-H2 of GD1a suggesting that the two oligosaccharide chains of the dimeric ganglioside form a single epitope recognized by a single-antibody domain. The availability of a method capable to prepare several hybrid gangliosides, and the availability of simple analytical approaches, opens new perspectives for the understanding and the therapy of several neuropathies.     

Forest plant diversity is threatened by Robinia pseudoacacia (black-locust) invasion

The effects of black-locust invasion on plant forest diversity are still poorly investigated. Vascular plants are likely to be influenced by increasing nutrient availability associated with the nitrogen-fixing activity of black-locust, whereas it is not clear if, along with stand aging, black-locust formations regain forest species. The main aim of the present study was to test whether the increase of black-locust stand age promoted a plant variation in mature stands leading to assemblages similar to those of native forests. Therefore, plant richness and composition of stands dominated by native trees were compared with pure black-locust stands of different successional stages. Our study confirmed that the replacement of native forests by pure black-locust stands causes both plant richness loss and shifts in species composition. In black-locust stands plant communities are dominated by nitrophilous species and lack many of the oligothrophic and acidophilus species typical of native forests. Plant communities of native forests are more diverse with respect to pure black-locust stands, suggesting that black-locust invasion also causes a homogenization of the plant forest biota. We did not detect differences across the successional gradient of black-locust stands, and mature stands do not recover the diversity of plant species which are lost by the replacement of the native forests by black-locust. Accordingly some efforts in reducing the negative impacts of black-locust invasion on plant forest biota should be focused at least in those areas where conservation is among management priorities, such in the case of habitats included in the Habitat Directive (92/43 ECE).     

Langerhans's cell histiocytosis in old subjects: two rare case reports and review of the literature

doi: 10.1111/j.1741‐2358.2012.00629.x Langerhans’s cell histiocytosis in old subjects: two rare case reports and review of the literature Background: Langerhans cell histiocytosis (LCH) is a proliferative disease of histiocyte‐like cells that generally affects children; LCH onset is rare in adults; immunohistochemistry is essential to obtain the correct diagnosis, and treatment protocols are controversial. Objective: To describe two new cases of adult onset oral LCH. Case reports: Case 1: a 71‐year‐old woman, complaining of diffuse oral pain, presented with erythematous mucosal lesions; the panoramic radiograph and CT scan showed multiple mandible radiolucent areas. Immunohistochemical assay for S‐100, CD1a and langerin test was essential in reaching the correct diagnosis. Case 2: a 77‐year‐old female patient presented with a non‐painful, non‐bleeding, slightly elevated erythematous palatal lesion of 6 months duration, together with a genital vulvar lesion of uncertain nature. The pathology confirmed the diagnosis of LCH. Many therapies (etoposid, radiotherapy) could induce only a clinical partial remission; Cladribine induced a complete recovery. Conclusion: The first case was difficult to diagnose: the clinical presentation and course of the disease (LCH) in the elderly are multiple and unpredictable. An immunohistochemistry study is often essential to obtain the correct diagnosis. The second case required several therapeutic interventions: even though some cases regress spontaneously, others require systemic chemotherapy.     

Novel S-acyl glutathione derivatives prevent amyloid oxidative stress and cholinergic dysfunction in Alzheimer disease models

Oxidative stress-mediated neuronal death may be initiated by a decrease in glutathione (GSH), whose levels are reduced in mitochondrial and synaptosomal fractions of specific CNS regions in Alzheimer disease (AD) patients. Currently, the use of GSH as a therapeutic agent is limited by its unfavorable pharmacokinetic properties. In this study, we designed the synthesis of new S-acyl glutathione (acyl-SG) thioesters of fatty acids via N-acyl benzotriazole-intermediate production and investigated their potential for targeted delivery of the parent GSH and free fatty acid to amyloid-exposed fibroblasts from familial AD patients and human SH-SY5Y neuroblastoma cells. Cell culture supplementation with acyl-SG derivatives triggers a significant decrease in lipid peroxidation and mitochondrial dysfunction in a fatty acid unsaturation degree-dependent fashion. Acyl-SG thioesters also protect cholinergic neurons against Aβ-induced damage and reduce glial reaction in rat brains. Collectively, these findings suggest that acyl-SG thioesters could prove useful as a tool for controlling AD-induced cerebral deterioration.     

Tissue distribution and metabolism of guanosine in rats following intraperitoneal injection

Guanosine has long been known as an endogenous purine nucleoside deeply involved in the modulation of several intracellular processes, especially G-protein activity. More recently, it has been reported to act as an extracellular signaling molecule released from neurons and, more markedly, from astrocytes either in basal conditions or after different kinds of stimulation including hypoxia. Moreover, in vivo studies have shown that guanosine plays an important role as both a neuroprotective and neurotrophic agent in the central nervous system. Specific high-affinity binding sites for this nucleoside have been found on membrane preparations from rat brain. The present study was undertaken to investigate the distribution and metabolic profiles of guanosine after administering the nucleoside to gain a better understanding of the biological effects of this potential drug candidate. Rats were given an intraperitonal (i.p.) injection of 2, 4, 8 or 16 mg/kg of guanosine combined with 0.05% of [3H]guanosine. Plasma samples were collected 7.5, 15, 30, 60 and 90 min after the guanosine-mixture administration and analyzed by either a liquid scintillation counter or by HPLC connected to a UV and to an on-line radiochemical detector to measure the levels of guanosine and its metabolic products guanine, xanthine and uric acid. The levels of guanosine, guanine and xanthine were also measured in brain, lung, heart, kidney and liver tissue homogenates at the defined time points after the injection of 8 mg/kg of the guanosine-mixture. We found that the levels of radioactivity in plasma increased linearly in a dose- and time-dependent manner. Guanosine was widely distributed in all tissues examined in the present study, at almost twice its usual levels. In addition, guanine levels dramatically increased in all the organs. Interestingly, enzymatic analysis of the plasma samples showed the presence of a soluble purine nucleoside phosphorylase, a key enzyme in the purine salvage pathway and nucleoside catabolism. Since guanosine has been shown to be neuroprotective and astrocytes have been reported to play critical roles in mediating neuronal survival and functions in different neurodegenerative disorders, we also performed uptake and release.