Scientific Publications
Lysosome‐associated protein transmembrane‐4 beta (LAPTM4B) has two alleles named as LAPTM4B*1 and LAPTM4B*2 (GenBank No. AY219176 and AY219177). Allele *1 has a single copy of a 19‐bp sequence in the 5` untranslated region (5`UTR), but allele *2 contains tandem repeats of 19‐bp sequence. LAPTM4B gene is located on long chromosome 8 (8q22.1) and contains seven exons that encodes two isoforms of tetratransmembrane proteins, LAPTM4B‐24 and LAPTM4B‐35, with molecular weights of 25 kDa and 35 kDa respectively. The LAPTM4B‐35′s primary structure is formed by 317 amino acid residues, and LAPTM4B‐24 comprised 226 amino acids. LAPTM4B, an integral membrane protein, contains several lysosomal‐targeting motifs at the C terminus and colocalizes with late endosomal and lysosomal markers. LAPTM4B is a proto‐oncogene, which becomes up‐regulated in various cancers. Preceding studies have examined the possible link between LAPTM4B polymorphism and susceptibility to several cancers,but the findings are still inconsistent. Hence, the present meta‐analysis was designed to investigate the impact of LAPTM4B polymorphism on risk of cancer.
This study was designed to evaluate the relationship between Programmed cell death protein 6 (PDCD6) polymorphisms and cancer susceptibility. The online databases were searched for relevant case-control studies published up to November 2017. Review Manage (RevMan) 5.3 was used to conduct the statistical analysis. The pooled odds ratio (OR) with its 95% confidence interval (CI) was employed to calculate the strength of association. Overall, our results indicate that PDCD6 rs3756712 T>G polymorphism was significantly associated with decreased risk of cancer under codominant (OR = 0.82, 95%CI = 0.70–0.96, p = 0.01, TG vs TT; OR = 0.53, 95%CI = 0.39-0.72, p < 0.0001, GG vs TT), dominant (OR = 0.76, 95%CI = 0.66-0.89, p = 0.0004, TG+GG vs TT), recessive (OR = 0.57, 95%CI = 0.43-0.78, p = 0.0003, GG vs TT+TG), and allele (OR = 0.76, 95%CI = 0.67–0.86, p < 0.00001, G vs T) genetic model. The finding did not support an association between rs4957014 T>G polymorphism of PDCD6, and different cancers risk.
With the rapid advancement of regenerative medicine technologies, there is an urgent need for the development of new, cell-friendly techniques for obtaining nanofibers—the raw material for an artificial extracellular matrix production. We investigated the structure and properties of PCL10 nanofibers, PCL5/PCL10 core-shell type nanofibers, as well as PCL5/PCLAg nanofibres prepared by electrospinning. For the production of the fiber variants, a 5–10% solution of polycaprolactone (PCL) (Mw = 70,000–90,000), dissolved in a mixture of formic acid and acetic acid at a ratio of 70:30 m/m was used. In order to obtain fibers containing PCLAg 1% of silver nanoparticles was added. The electrospin was conducted using the above-described solutions at the electrostatic field. The subsequent bio-analysis shows that synthesis of core-shell nanofibers PCL5/PCL10, and the silver-doped variant nanofiber core shell PCL5/PCLAg, by using organic acids as solvents, is a robust technique. Furthermore, the incorporation of silver nanoparticles into PCL5/PCLAg makes such nanofibers toxic to model microbes without compromising its biocompatibility. Nanofibers obtained such way may then be used in regenerative medicine, for the preparation of extracellular scaffolds: (i) for controlled bone regeneration due to the long decay time of the PCL, (ii) as bioscaffolds for generation of other types of artificial tissues, (iii) and as carriers of nanocapsules for local drug delivery. Furthermore, the used solvents are significantly less toxic than the solvents for polycaprolactone currently commonly used in electrospin, like for example chloroform (CHCl3), methanol (CH3OH), dimethylformamide (C3H7NO) or tetrahydrofuran (C4H8O), hence the presented here electrospin technique may allow for the production of multilayer nanofibres more suitable for the use in medical field.
Adipose tissue is a promising source of mesenchymal stem cells. Their potential to differentiate and regenerate other types of tissues may be affected by several factors. This may be due to in vitro cell-culture conditions, especially the supplementation with antibiotics. The aim of our study was to evaluate the effects of a penicillin-streptomycin mixture (PS), amphotericin B (AmB), a complex of AmB with copper (II) ions (AmB-Cu2+) and various combinations of these antibiotics on the proliferation and differentiation of adipose-derived stem cells in vitro. Normal human adipose-derived stem cells (ADSC, Lonza) were routinely maintained in a Dulbecco’s Modified Eagle Medium (DMEM) that was either supplemented with selected antibiotics or without antibiotics. The ADSC that were used for the experiment were at the second passage. The effect of antibiotics on proliferation was analyzed using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) and sulforhodamine-B (SRB) tests. Differentiation was evaluated based on Alizarin Red staining, Oil Red O staining and determination of the expression of ADSC, osteoblast and adipocyte markers by real-time RT-qPCR. The obtained results indicate that the influence of antibiotics on adipose-derived stem cells depends on the duration of exposure and on the combination of applied compounds. We show that antibiotics alter the proliferation of cells and also promote natural osteogenesis, and adipogenesis, and that this effect is also noticeable in stimulated osteogenesis.
Microbubble-based ultrasound contrast agents are used in clinical settings to enhance backscattered ultrasound signals from blood during perfusion and blood flow measurements. The dynamics of microbubbles contained in ultrasound contrast agents are typically studied with a high-speed camera attached to a microscope. Such microbubbles, with resting diameters between 1 µm and 7 µm, are considered in optical focus if the bubble centers are in the focal plane of the objective lens. Nonetheless, when a three-dimensional object, a stack of infinitely thin two-dimensional layers, is imaged through a microscope, the image formed onto the charge coupled device element consists of contributions from all layers. If a bubble is larger than the depth of focus, the part of the bubble above the focal plane influences the image formation and therefore the bubble size measured. If a bubble is of a size in the order of the wavelengths of the light used, the system resolution and the segmentation method influence the bubble size measured. In this study, the projections of three dimensional microbubbles (hollow spheres) were computed with an ideal, weighted three-dimensional point spread function to find out under which circumstances the optical image formation leads to a significant deviation in measurement of the actual size. The artificial images were subjected to segmentation techniques for objectively comparing original microbubble sizes with measured microbubble sizes. Results showed that a systematic error was observed for objects in focus with radius ≤ 1.65µm. Also it was concluded that even though a three-dimensional object is in focus, there is discrepancy of up to 0.66% in size measurement. In addition, size measurement of an object for the same shift above and below focus could differ by up to 3.6%. Moreover, defocusing above 25% severely deviates size measurements while defocusing up to 90% could result in mean percentage error of up to 67.96.
An antibubble is a gas bubble containing a liquid droplet core. Both the droplet and the gas bubble are typically surrounded by stabilising shells. Owing to electrostatic forces exerted by these shells, core droplets of micrometer diameter do not readily coalesce with the surrounding liquid medium. Owing to the incompressibility of the liquid droplet core, antibubbles will oscillate asymmetrically, i.e., the radial excursion amplitude of the surface is greater during expansion than during contraction, when subjected to diagnostic ultrasound. Consequently, the harmonic content of the ultrasound signal radiated from antibubbles must be higher than that from identical bubbles without a liquid core. Whether the harmonic signal component generated by physical antibubbles is higher than the harmonic component of identical bubbles without a core has been studied here. We subjected prefabricated antibubbles and identical bubbles without core droplets to 1-MHz ultrasound and to a commercial ultrasound system, and recorded the spectra with a broadband transducer oriented perpendicularly to the transmitter. Normalised by the acoustic response from the medium, the antibubble signal shows stronger higher harmonics than the reference signal, and negligible fundamental response. In conclusion, antibubbles are suitable candidates for harmonic imaging. The generation of higher harmonics without fundamental has been attributed to asymmetric antibubble expansion.
The ability to exclude harmful factors from a hydrogel microbead is important for the degree of protection the beads offers to what is encapsulated within. The permeability of alginate microbeads, prepared by water-in-oil emulsification, was investigated by their ability to exclude FITC-labelled protein probes. The influence of alginate concentration, calcium concentration and method of addition, and salt content of the environment was investigated. The permeability was also compared to the permeability of beads made by the traditional method of dripping an alginate solution into a CaCl2 solution. Beads produced with low amounts of CaCl2 show a significant degree of swelling and are therefore very permeable (C/C0 (BSA) = 0.62, where C is the final concentration of BSA-FITC in the bead, and C0 the concentration of BSA-FITC in the continuous phase). With additional calcium, either by adding more calcium crystals after the emulsification step or by washing with a CaCl2 solution, beads swell less and are less permeable (C/C0 (BSA) = 0.13 and 0.12). Beads made by dripping are very permeable (C/C0 (BSA) ∼ 0.60). Because in this process the droplets of alginate are not constrained by a water-oil boundary, the beads can swell during gelation. The salt concentration in the continuous phase influences the strength of the electrostatic repulsion between the probes and the alginate network and hence affects the permeation of the probes into the beads. In the absence of salt, even FITC (389Da) is mostly excluded from the interior of the beads (C/C0 (FITC) ∼ 0.09).
Triatomines are insect vectors of Trypanosoma cruzi¸ the etiological agent of Chagas disease. Several species belonging to the genus Rhodnius (Hemiptera: Reduviidae) have been reported inhabiting domestic and peridomestic environments in different regions of Latin America. However, behavioral and sensory ecology aspects related to their use of shelters have been poorly studied. The objective of the present study was to characterize how bug density, illumination and thigmotactic information affect the use of shelters by three species belonging to the Rhodnius prolixus species complex. We evaluated whether exposure to different insect densities affects the proportion of R. prolixus, Rhodnius robustus and Rhodnius neglectus that choose to stay inside a refuge. Besides, we evaluated whether absence of an illumination regime affects their tendency to hide in shelters. Our results showed that the proportion of individuals that remained outside the shelter increased with rising insect densities. Nevertheless, while R. prolixus only reacted by augmenting this proportion with the highest density tested, the other species showed significant increases already at lower densities. On the other hand, a significantly higher number of R. robustus stayed outside the shelter in the absence of a light cycle, while no change was induced for the other species. Thus, this study determined species-specific profiles of refuge exploitation defined by factors such as thigmotaxis and negative phototaxis. The differences observed among these Rhodnius species may impact their house colonization abilities, which seem to be critically affected by bug hiding performance during health service detection processes.
Background The triatomine bug Rhodnius prolixus Stål, 1859 (Heteroptera: Reduviidae) is the primary vector of Chagas disease in Colombia and Venezuela. An important step in controlling Chagas disease is monitoring the growth and spread of bug populations to inform effective management. Such monitoring could be carried out using pheromone traps. To develop effective pheromone traps, it is vital to understand the pheromone chemistry of R. prolixus. Previous studies have found that female R. prolixus metasternal gland secretions induce males to: leave shelters, take off, orientate during walking, aggregate around mating pairs, and mate. This study aims to identify a synthetic blend of female metasternal gland compounds that could be used to attract R. prolixus. Results We investigated the electrophysiological activity of the ten most abundant compounds in female R. prolixus metasternal glands using single sensillum recordings. In total we obtained 60 recordings from basiconic sensilla in male R. prolixus. In 31 of these recordings, responses to individual compounds were observed. Each of the ten tested compounds elicited neuron responses in a minimum of eight recordings. Having confirmed their electrophysiological activity, we tested these ten compounds by presenting them to male Rhodnius prolixus in a “T” olfactometer. Male bugs showed a significant preference for the blend of metasternal gland compounds compared to the clean air control. Conclusions A simple blend of ten compounds found in female R. prolixus metasternal glands is attractive to conspecific males. All compounds in the blend are either commercially available at low cost, or easily synthetically prepared from simple precursors. We hope that this blend will be evaluated as a lure for pheromone traps in field bioassays.
The triatomine bug Rhodnius prolixus is a main vector of Chagas disease, which affects several million people in Latin-America. These nocturnal insects spend most of their locomotory activity during the first hours of the scotophase searching for suitable hosts. In this study we used multivariate analysis to characterize spontaneous locomotory activity profiles presented by 5th instar nymphs. In addition, we investigated whether sex and the expression of the foraging (Rpfor) gene could modulate this behavioral trait. Hierarchical Clustering and Redundancy Analyses detected individuals with distinct locomotory profiles. In addition to a great variation in locomotory intensity, we found that a proportion of nymphs walked during unusual time intervals. Locomotory activity profiles were mostly affected by the cumulative activity expressed by the nymphs. These effects promoted by cumulative activity were in turn influenced by nymph sex. Sex and the Rpfor expression had a significant influence on the profiles, as well as in the levels of total activity. In conclusion, the locomotory profiles evinced by the multivariate analyses suggest the co-existence of different foraging strategies in bugs. Additionally, we report sex-specific effects on the locomotion patterns of 5th instar R. prolixus, which are apparently modulated by the differential expression of the Rpfor gene.