A spectrofluorometric analysis to evaluate transcutaneous biodistribution of fluorescent nanoparticulate gel formulations

The investigation of the absorption of drug delivery systems, designed for the transport of therapeutic molecules inside the body, could be relatively simplified by the fluorophore association and tracking by means of bio-imaging techniques (i.e., optical in vivo imaging or confocal and multiphoton microscopy). However, when a fluorescence signal comes out from the skin, its specific detection can be problematic. Skin high autofluorescence can hinder the observation of administered exogenous fluorophores conjugated to drug delivery systems, making it more challenging to detect their biodistribution. In the present study, we have developed a method based on the spectrofluorometric analysis of skin samples to discriminate the fluorescent signal coming from administered fluorescent molecules from the background. Moreover, we gave a semi-quantitative evaluation of the signal intensity. Thus, we distinguished two gel formulations loading the fluorophore rhodamine B (called GEL RHO and GEL SLN-RHO). The two formulations of gels, one of which containing solid lipid nanoparticles (GEL RHO-SLN), were administered on skin explants incubated in a bioreactor, and the penetration was evaluated at different time points (2 and 6 hours). Cryostatic sections of skin samples were observed with confocal laser scanning microscopy, and a spectrofluorometric analysis was performed. Significantly higher signal intensity in the samples administered with SLN-RHO GEL, with a preferential accumulation in the hair bulbs, was found. Reaching also the deeper layers of the hair shaft after 6 hours, the solid lipid nanoparticles thickened with polymer represent a suitable drug delivery system for transcutaneous administration.Key words: Organ culture, bioreactor, transcutaneous biodistribution, spectrofluorimetric analysis     

Fire ants: What do rural and urban areas show us about occurrence, diversity,and ancestral state reconstruction?

In South America, Solenopsis saevissima and S. invicta are the most common fire ants. Nests are founded in areas under anthropic interference like urban or rural areas, but S. invicta is found preferentially in those with the greatest anthropic interference. However, we do not know the rates at which they exist in anthropized areas next to high density of native vegetation. Areas with 60 to 90% of native Atlantic Forest were selected to verify the occurrence of both species in rural and urban areas. We investigated the molecular diversity and applied the reconstruction of the ancestral state analysis for each species. A total of 186 nests were analyzed and we found that the two species had the same proportion in the urban area. However, S. saevissima had a higher rate of prevalence in the rural area, in addition to having a greater number of haplotypes and ancestry associated with this type of habitat for the region. S. invicta had the same number of haplotypes in both rural and urban regions, and less haplotypic diversity. We conclude that S. saevissima is a species typically associated with rural areas and S. invicta, although present, is not dominant in urban areas. Keywords: Biodiversity, haplotype diversity, DNA barcoding, mtDNA     

Molecular,Viral and Clinical Features of Alcohol- and Non-Alcohol-Induced Liver Injury

Hepatic cells are sensitive to internal and external signals. Ethanol is one of the oldest and most widely used drugs in the world. The focus on the mechanistic engine of the alcohol-induced injury has been in the liver, which is responsible for the pathways of alcohol metabolism. Ethanol undergoes a phase I type of reaction, mainly catalyzed by the cytoplasmic enzyme, alcohol dehydrogenase (ADH), and by the microsomal ethanol-oxidizing system (MEOS). Reactive oxygen species (ROS) generated by cytochrome (CYP) 2E1 activity and MEOS contribute to ethanol-induced toxicity. We aimed to: (1) Describe the cellular, pathophysiological and clinical effects of alcohol misuse on the liver; (2) Select the biomarkers and analytical methods utilized by the clinical laboratory to assess alcohol exposure; (3) Provide therapeutic ideas to prevent/reduce alcohol-induced liver injury; (4) Provide up-to-date knowledge regarding the Corona virus and its affect on the liver; (5) Link rare diseases with alcohol consumption. The current review contributes to risk identification of patients with alcoholic, as well as non-alcoholic, liver disease and metabolic syndrome. Additional prevalence of ethnic, genetic, and viral vulnerabilities are presented.     

Immobilization-dependent bone collagen breakdown appears to increase with time: evidence for a lack of new bone equilibrium in response to reduced load during prolonged bed rest.

The purpose of this study was to evaluate the effect of prolonged immobilization on bone, in order to investigate how skeletal turnover adapts to bed rest. We examined indices of bone formation and bone resorption in the serum and urine of fifty-four patients (26 males and 28 females) immobilized after an episode of paralytic stroke. The length of immobilization ranged from 30 to 180 days. A significant, time-dependent increase in markers of resorption - urinary pyridinoline (Pyr) and deoxypyridinoline (D-Pyr), serum Type I collagen cross-linked C-telopeptide (ICTP) - was observed in immobilized patients, as compared to free-living healthy subjects. The positive correlation between resorption markers increase and the length of immobilization suggests that the rate of bone resorption did not decrease with time. On the other hand, the levels of markers of bone formation - bone-specific alkaline phosphatase (B-ALP), and the carboxyl-terminal propeptide of Type I procollagen (PICP) - remained within the normal range in all patients, regardless the length of immobilization. Our results would indicate an uncoupling between bone formation and bone resorption during bed rest, and suggest that the bone collagen break-down was not a self-limiting process in immobilized patients, and that a new equilibrium or "steady state" in response to the reduced load was not reached in the skeleton.     

Metabolic engineering of the terpenoid biosynthetic pathway of Escherichia coli for production of the carotenoids β-carotene and zeaxanthin

Metabolic engineering of the early non-mevalonate terpenoid pathway of Escherichia coli was carried out to increase the supply of prenyl pyrophosphates as precursor for carotenoid production. Transformation with the genes dxs for over-expression of 1-deoxy-d-xylulose 5-phosphate synthase, dxr for 1-deoxy-d-xylulose 5-phosphate reductoisomerase and idi encoding an isopentenyl pyrophosphate stimulated carotenogenesis up to 3.5-fold. Co-transformation of idi with either dxs or dxr had an additive effect on ß-carotene and zeaxanthin production which reached 1.6 mg g^–1 dry wt.     

Respiratory Chains from Aerobic Thermophilic Prokaryotes

Thermophiles are organisms that grow optimally above 50 degrees C and up to approximately 120 degrees C. These extreme conditions must have led to specific characteristics of the cellular components. In this paper we extensively analyze the types of respiratory complexes from thermophilic aerobic prokaryotes. The different membrane-bound complexes so far characterized are described, and the genomic data available for thermophilic archaea and bacteria are analyzed. It is observed that no specific characteristics can be associated to thermophilicity as the different types of complexes I-IV are present randomly in thermophilic aerobic organisms, as well as in mesophiles. Rather, the extensive genomic analyses indicate that the differences concerning the several complexes are related to the organism phylogeny, i.e., to evolution and lateral gene transfer events.     

Morphine induces terminal micro-opioid receptor desensitization by sustained phosphorylation of serine-375

Morphine is a poor inducer of micro-opioid receptor (MOR) internalization, but a potent inducer of cellular tolerance. Here we show that, in contrast to full agonists such as [D-Ala(2)-MePhe(4)-Gly-ol]enkephalin (DAMGO), morphine stimulated a selective phosphorylation of the carboxy-terminal residue 375 (Ser(375)). Ser(375) phosphorylation was sufficient and required for morphine-induced desensitization of MOR. In the presence of full agonists, morphine revealed partial agonistic properties and potently inhibited MOR phosphorylation and internalization. Upon removal of the drug, DAMGO-desensitized receptors were rapidly dephosphorylated. In contrast, morphine-desensitized receptors remained at the plasma membrane in a Ser(375)-phosphorylated state for prolonged periods. Thus, morphine promotes terminal MOR desensitization by inducing a persistent modification of Ser(375).