Fluorescence imaging in vivo: recent advances

In vivo fluorescence imaging uses a sensitive camera to detect fluorescence emission from fluorophores in whole-body living small animals. To overcome the photon attenuation in living tissue, fluorophores with long emission at the near-infrared (NIR) region are generally preferred, including widely used small indocarbocyanine dyes. The list of NIR probes continues to grow with the recent addition of fluorescent organic, inorganic and biological nanoparticles. Recent advances in imaging strategies and reporter techniques for in vivo fluorescence imaging include novel approaches to improve the specificity and affinity of the probes and to modulate and amplify the signal at target sites for enhanced sensitivity. Further emerging developments are aiming to achieve high-resolution, multimodality and lifetime-based in vivo fluorescence imaging.     

Topical Reappraisal of Molecular Pharmacological Approaches to Endothelial Dysfunction in Diabetes Mellitus Angiopathy

Diabetes mellitus (DM) is a frequent medical problem, affecting more than 4% of the population in most countries. In the context of diabetes, the vascular endothelium can play a crucial pathophysiological role. If a healthy endothelium—which is a dynamic endocrine organ with autocrine and paracrine activity—regulates vascular tone and permeability and assures a proper balance between coagulation and fibrinolysis, and vasodilation and vasoconstriction, then, in contrast, a dysfunctional endothelium has received increasing attention as a potential contributor to the pathogenesis of vascular disease in diabetes. Hyperglycemia is indicated to be the major causative factor in the development of endothelial dysfunction. Furthermore, many shreds of evidence suggest that the progression of insulin resistance in type 2 diabetes is parallel to the advancement of endothelial dysfunction in atherosclerosis. To present the state-of-the-art data regarding endothelial dysfunction in diabetic micro- and macroangiopathy, we constructed this literature review based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). We interrogated five medical databases: Elsevier, PubMed, PMC, PEDro, and ISI Web of Science.     

Human Gender Differences in the Perception of Conspecific Alarm Chemosensory Cues

It has previously been established that, in threatening situations, animals use alarm pheromones to communicate danger. There is emerging evidence of analogous chemosensory “stress” cues in humans. For this study, we collected alarm and exercise sweat from “donors,” extracted it, pooled it and presented it to 16 unrelated “detector” subjects undergoing fMRI. The fMRI protocol consisted of four stimulus runs, with each combination of stimulus condition and donor gender represented four times. Because olfactory stimuli do not follow the canonical hemodynamic response, we used a model-free approach. We performed minimal preprocessing and worked directly with block-average time series and step-function estimates. We found that, while male stress sweat produced a comparably strong emotional response in both detector genders, female stress sweat produced a markedly stronger arousal in female than in male detectors. Our statistical tests pinpointed this gender-specificity to the right amygdala (strongest in the superficial nuclei). When comparing the olfactory bulb responses to the corresponding stimuli, we found no significant differences between male and female detectors. These imaging results complement existing behavioral evidence, by identifying whether gender differences in response to alarm chemosignals are initiated at the perceptual versus emotional level. Since we found no significant differences in the olfactory bulb (primary processing site for chemosensory signals in mammals), we infer that the specificity in responding to female fear is likely based on processing meaning, rather than strength, of chemosensory cues from each gender.     

Low genetic variability of <Emphasis Type="Italic">Rhinolophus mehelyi</Emphasis> (Mehely's horseshoe bat) in Romania

Rhinolophus mehelyi (Mehely's horseshoe bat) is a vulnerable species with an increasingly fragmented distribution. In Romania, populations of R. mehelyi have experienced a dramatic decline over the past 50 years, and the current population size is estimated at only 100 adult individuals inhabiting almost exclusively the Limanu cave. In the present study, we investigated the genetic consequences of population decline for the viability of the remaining population of R. mehelyi in Romania. We sequenced and analyzed a 359-bp fragment of the mitochondrial control region from the only known Romanian population and compared it with two geographically close colonies from Bulgaria. A single haplotype was found in the Romanian population compared to 10 in the Bulgarian population, suggesting genetic isolation.     

SunCHem: an integrated process for the hydrothermal production of methane from microalgae and CO2 mitigation

We describe a potential novel process (SunCHem) for the production of bio-methane via hydrothermal gasification of microalgae, envisioned as a closed-loop system, where the nutrients, water, and CO₂ produced are recycled. The influence on the growth of microalgae of nickel, a trace contaminant that might accumulate upon effluent recycling, was investigated. For all microalgae tested, the growth was adversely affected by the nickel present (1, 5, and 10 ppm). At 25 ppm Ni, complete inhibition of cell division occurred. Successful hydrothermal gasification of the microalgae Phaeodactylum tricornutum to a methane-rich gas with high carbon gasification efficiency (68–74%) and C1–C3 hydrocarbon yields of 0.2 g_C1–C3/g_DM (DM, dry matter) was demonstrated. The biomass-released sulfur was shown to adversely affect Ru/C catalyst performance. Liquefaction of P. tricornutum at short residence times around 360°C was possible without coke formation.     

A multi-etiology model of systemic degeneration in schizophrenia

We discuss the possibility of multiple underlying etiologies of the condition currently labeled as schizophrenia. We support this hypothesis with a theoretical model of the prefrontal-limbic system.We show how the dynamical behavior of this model depends on an entire set of physiological parameters, representing synaptic strengths, vulnerability to stress-induced cortisol, dopamine regulation and rates of autoantibody production. Malfunction of such different parameters produces similar outward dysregulation of the system, which may readily lead to diagnostic difficulties for a clinician.Techniques that provide a spectrum/profile of neural and steroid functions may be helpful in clarifying these diagnostic dilemmas.     

Molecular processes in the streptokinase thrombolytic therapy

The aim of this research is to evaluate the current streptokinase thrombolytic treatment and to identify or improve new techniques that will base new approaches with a higher efficiency in this area of expertise. In order to be as realistic as possible a new method was set up using magnetic vectorized nanoparticles streptokinase and human blood thrombus. The experimental data confirm the maximum 83% thrombus lyses whenever increase streptokinase concentration. It is very probable to happen because of the presence of high concentration of antiplasmin in the blood that neutralizes around half of the thrombolytic potential of the sanguine plasminogen. The experiment shows also that only free serum plasminogen are available for streptokinase action in order to generate plasmin.     

Complexation of lipofectamine and cholesterol-modified DNA sequences studied by single-molecule fluorescence techniques

Lipoplex formation for normal and cholesterol-modified oligonucleotides is investigated by fluorescence correlation spectroscopy (FCS). To overcome the problems related to the fitting of autocorrelation curves when fluorescence bursts are present, the baseline fluorescence levels and the fluorescence bursts in the same trace were separately analyzed. This approach was not previously used in FCS studies of lipoplexes and allowed a more detailed characterization of this heterogeneous system. From the baseline levels, the number of free/bound DNA molecules and the presence of tens to hundreds of nanometer-sized lipoplexes were estimated using various mathematical models. Analysis of the fluorescent bursts provided an indication about the sizes of the lipoplexes, the number of DNA molecules in these aggregates, and the relative amount of lipids in each aggregate. An explanation for the higher transfection efficiency previously reported for one of the cholesterol-modified oligonucleotide compounds was found in relation to the formation of large size lipoplexes.