Short-wave and near infrared π-conjugated polymers hosted in a biocompatible microemulsion: a pioneering approach for photoacoustic contrast agents

In the present study a biocompatible oil-in-water (O/W) microemulsion was developed carrying short-wave infrared (SWIR) π-conjugated polymers and possessing photoacoustic properties for the first time. SWIR and NIR absorbing conjugated polymers were accomplished to be dissolved in a Food & Drug Administration (FDA) approved natural oil limonene, to formulate an O/W microemulsion using biocompatible surfactants (Span80, Labrasol®). Detailed structural characterization in the absence and presence of the polymers was performed by means of dynamic light scattering (DLS), small-angle X-ray scattering (SAXS) and electron paramagnetic resonance (EPR) spectroscopy. In terms of biological evaluation of the loaded microemulsions, inhibition of cell proliferation in various cancer cell lines without exhibiting significant cytotoxicity was tested through the MTT assay. The developed π-conjugated polymers hosted in O/W microemulsions represent a technological approach with a wide range of biomedical and bioelectronic applications and in this contribution, their photoacoustic properties are presented as a proof-of-concept.

Physicochemical Characteristics of Four Limonene-Based Nanoemulsions and Their Larvicidal Properties against Two Mosquito Species, Aedes albopictus and Culex pipiens molestus

Negative impacts on the environment from the continuous use of synthetic insecticides against mosquitoes has driven research towards more ecofriendly products. Phytochemicals, classified as low-risk substances, have been recognized as potential larvicides of mosquitoes; however, problems related to water solubility and stability are limiting factors for their use in mosquito control programs in the field. In this context, many researchers have focused on formulating essential oils in nanoemulsions, exploiting innovative nanotechnology. In the current study, we prepared 4 (R)-(+)-limonene oil-in-water nanoemulsions using low and high energy methods, and we evaluated their physicochemical characteristics (e.g., viscosity, stability, mean droplet diameter, polydispersity index) and their bioactivity against larvae of two mosquito species of great medical importance, namely, Cx. pipiens molestus and Ae. albopictus. According to the dose-response bioassays with the limonene-based nanoemulsions and pure limonene (dissolved in organic solvent), the tested nanoformulations improved the activity of limonene against Ae. albopictus larvae, while the performance of limonene was either the same or better than limonene against Cx. pipiens molestus, depending on the applied system. Overall, we achieved the production of limonene-based delivery nanosystems, with sufficient lethal properties against mosquito larvae to consider them promising larvicidal formulations applicable to mosquito breeding sites.

Oil-In-Water Microemulsions as Hosts for Benzothiophene-Based Cytotoxic Compounds: An Effective Combination

Targeted delivery of chemotherapeutics in order to overcome side effects and enhance chemosensitivity remains a major issue in cancer research. In this context, biocompatible oil-in-water (O/W) microemulsions were developed as matrices for the encapsulation of DPS-2 a benzothiophene analogue, exhibiting high cytotoxicity in various cancer cell lines, among them the MW 164 skin melanoma and Caco-2 human epithelial colorectal adenocarcinoma cell lines. The microemulsion delivery system was structurally characterized by dynamic light scattering (DLS) and electron paramagnetic resonance (EPR) spectroscopy. The effective release of a lipophilic encapsulated compound was evaluated via confocal microscopy. The cytotoxic effect, in the presence and absence of DPS-2, was examined through the thiazolyl blue tetrazolium bromide (MTT) cell proliferation assay. When encapsulated, DPS-2 was as cytotoxic as when dissolved in dimethyl sulfoxide (DMSO). Hence, the oil cores of O/W microemulsions were proven effective biocompatible carriers of lipophilic bioactive molecules in biological assessment experiments. Further investigation through fluorescence-activated cell sorting (FACS) analysis, comet assay, and Western blotting, revealed that DPS-2, although non-genotoxic, induced S phase delay accompanied by cdc25A degradation and a nonapoptotic cell death in both cell lines, which implies that this benzothiophene analogue is a deoxyribonucleic acid (DNA) replication inhibitor.

Drug nanocarriers for cancer chemotherapy based on microemulsions: The case of Vemurafenib analog PLX4720

Oil-in-water (O/W) microemulsions based on Tween 80 as the emulsifier and triacetin as the dispersed oil phase were formulated to be used as delivery vehicles of Vemurafenib analog PLX4720. PLX4720 is a lipophilic antitumor drug against various cancer types correlated with the BRAF^V600E mutation. The limits of the single-phase region corresponding to O/W microemulsions as described by ternary phase diagrams were examined. Droplet size measurements determined by dynamic light scattering (DLS) showed mean droplet diameters equal to 10±0.1nm both in the presence and in absence of the drug. Cryogenic-transmission electron microscopy (Cryo-TEM) images of the microemulsions showed the existence of small structures with uniform size distribution having also average diameters of approximately 10nm. Electron paramagnetic resonance (EPR) spectroscopy applying the spin probing technique confirmed PLX4720 location in the oil cores excluding its participation in the surfactants monolayer. Furthermore, cell viability assays on colon cancer cell lines Colo-205 and HT29 showed that microemulsions did not exhibit any cytotoxicity when added in ratios between 0.005% v/v and 0.2% v/v. When the cells were treated with encapsulated PLX4720 at two different concentrations (0.063 and 0.12μΜ) the same response as when dissolved in classic DMSO was observed.

Candida albicans chronic colonisation in cystic fibrosis may be associated with inhaled antibiotics

Candida albicans is increasingly recognised as a coloniser of the respiratory tract in cystic fibrosis (CF) patients. Yet, the potential role, if any, of the micro-organism in the progress of the disease remains unclear. In this study, we investigated the association between inhaled antibiotics and C. albicans chronic colonisation in patients with CF. A cohort of 121 CF patients born from 1988 to 1996 was, respectively, studied. The medical records of each patient were reviewed from the first time they attended the CF Centre until the occurrence of C. albicans chronic colonisation or their last visit for the year 2010. Chronic colonisation was defined as the presence of C. albicans in more than 50% of cultures in a given year. A number of possible confounders were included in the multivariate logistic regression analysis to identify an independent association between inhaled antibiotics and C. albicans chronic colonisation. Fifty-four (44.6%) of the 121 patients enrolled in the study developed chronic colonisation by the micro-organism. Multivariate logistic regression analysis determined the independent effect of inhaled antibiotic treatment on the odds of chronic colonisation (OR 1.112, 95% CI [1.007-1.229], P = 0.036). Candida albicans chronic colonisation may be associated with the duration of inhaled antibiotic treatment.

[Dementia and bipolar disorder on the borderline of old age]

Dementia and bipolar disorder have been traditionally considered two separate clinical entities. However, recent preclinical and clinical data in elderly people suggest that they are in fact related. Several theories have been put forward to interpret their relationship which could be summed up as follows: (1) Dementia could increase the risk for the emergence of bipolar symptoms, or (2) conversely, bipolar disorder might be associated with heightened risk for developing pseudodementia or dementia. (3) Alternatively, dementia, other brain diseases or drugs affecting brain function could lead to the combination of symptoms of dementia and bipolar disorder in elderly individuals. The two disorders demonstrate similarities with respect to their clinical expression (agitation, psychotic, mood and cognitive symptoms) and structural brain neuroimaging (enlarged lateral ventricles and white matter hyperintensities using magnetic resonance imaging-MRI). Despite the above similarities, the two disorders also have important differences. As expected, cognitive symptoms prevail in dementia and mood symptoms in bipolar disorder. In dementia but not in bipolar disorder there is evidence that brain structural abnormalities are diffuse and hippocampal volumes are smaller. Dementia and bipolar disorder present different abnormalities in functional brain neuroimaging. The pattern of "ventral" hyperactivity and "dorsal" hypoactivity in brain emotional circuits at rest is revealed in bipolar disorder but not dementia. With respect to their treatment, acetylcholinesterase inhibitors and memantine are indicated against cognitive symptoms in dementia and also improve behavioural and psychological symptoms appearing during the course of dementia. Lithium, anticonvulsants, antipsychotics and antidepressants are effective in the management of the acute episodes of bipolar disorder of younger adults, but there are not yet evidence-based data in elderly bipolar patients. It is likely that the efficacy of anticonvulsants and antipsychotics is superior during acute bipolar episodes in elderly individuals, although both drug categories have been associated with important adverse effects. Current data suggest that the best option during the maintenance phase of the elderly bipolar disorder is the continuation of agents which have been shown effective in the management of acute episodes. The appropriate treatment of cognitive symptoms in elderly bipolar patients has not been thoroughly investigated. In addition, the therapeutic value of psychotropics except cholinesterase inhibitors and memantine in dementia is still controversial, due to their association with side effects. Recent studies which have focused on the role of lithium in dementia could help clarify the relationship of dementia and elderly bipolar disorder. Although there are promising findings with respect to the value of lithium treatment in the prevention of dementia, the existing clinical studies do not support any beneficial effect of lithium administration on enhancing cognitive functioning of people with dementia. The specific role of lithium in dementia and the preventive value of interventions against vascular risk factors in both disorders remain to be evaluated in future prospective studies.

[Use of antiepileptic drugs in schizophrenia: A review of recent evidence]

The treatment of schizophrenia has always been a challenge for clinicians. Neuroleptic monotherapy is not sufficient in all subtypes and all symptoms of schizophrenia. New treatment strategies have been developed including the combination of neuroleptics and antiepileptics. We summarize papers published on the efficacy and the action mechanism of antiepileptic agents in schizophrenia. We have searched the computer database system MEDLINE and COCHRANE for relevant articles. GABA and glutamate are involved in the symptom improvement of schizophrenia when antiepileptics are added in the main neuroleptic treatment. Augmentation treatment with valproate leads to a decrease in hostility, violent behavior, agitation and anxiety and is related to fewer days of hospitalization. Carbamazepine has been used as a calmative and is effective in controlling patients with psychomotor agitation. Whether both antiepileptics can reduce positive and negative symptoms in schizophrenia, still remains controversial. Oxcarbazepine has a very safe pharmaceutical profile in combination with neuroleptics but only a single study indicates its efficacy. Adjunctive lamotrigine appears effective when added to clozapine even in cases of treatment resistant schizophrenia. Both lamotrigine and clozapine share anti-glutamatergic actions. There have been reported few studies which support the use of topiramate in schizophrenia. Future studies on a great number of patients will provide more reliable evidence. Finally the potential role of new antiepileptics has to be evaluated using new clinical testing.

A novel homothallic variety of Agaricus bisporus comprises rare tetrasporic isolates from Europe

Among 400 wild specimens of A. bisporus collected in Europe, only three were tetrasporic. In the case of two of them from France, a previous study showed that one was homokaryotic and hypothetically belonged to a homothallic entity while the other was heterokaryotic and possibly resulted from hybridization between a member of this entity and a classical bisporic strain. A third tetrasporic specimen recently was discovered in Greece. Morphological and genetic comparisons, using alloenzymatic markers, molecular markers and ITS polymorphisms, reveal that this third specimen is homokaryotic and belongs, with the homokaryotic specimen from France, to the same entity. Dissimilarity analysis confirms the hybrid origin of the heterokaryotic specimen. Varietal status is proposed for this homothallic, highly homogeneous entity, and A. bisporus var. eurotetrasporus is described. This novel variety clearly differs from var. bisporus by its tetrasporic basidia and from var. burnettii by its longer spores. It has a complex story because it can interbreed with var. bisporus and shares the same habitat; however, because of its homothallic life cycle and its partial intersterility, it is probably in the process of speciation.