Tracking soluble and nanoparticulated titanium released in vivo from metal dental implant debris using (single-particle)-ICP-MS

BackgroundThis work studies the presence of the Ti, Al and V metal ions and Ti nanoparticles released from the debris produced by the implantoplasty, a surgical procedure used in the clinic, in rat organs.MethodsThe sample preparation for total Ti determination was carefully optimized using microsampling inserts to minimize the dilution during the acid attack of the lyophilized tissues by a microwave-assisted acid digestion method. An enzymatic digestion method was optimized and applied to the different tissue samples in order to extract the titanium nanoparticles for the single-particle ICP-MS analysis.ResultsA statistically significant increase was found for Ti concentrations from control to experimental groups for several of the studied tissues, being and particularly significant in the case of brain and spleen. Al and V concentrations were detected in all tissues but they were not different when comparing control and experimental animals, except for V in brain. The possible presence of Ti-containing nanoparticles mobilized from the implantoplasty debris was tested using enzymatic digestions and SP-ICP-MS. The presence of Ti-containing nanoparticles was observed in all the analyzed tissues, however, differences on the Ti mass per particle were found between the blanks and the digested tissue and between control and experimental animals in some organs.ConclusionThe developed methodologies, both for ionic and nanoparticulated metal contents in rat organs, have shown the possible increase in the levels of Ti both as ions and nanoparticles in rats subjected to implantoplasty.     

Selection and characterization of two monoclonal antibodies specific for the Aspergillus flavus major antigenic cell wall protein Aflmp1

Aspergillus flavus is a major fungal pathogen of plants and an opportunistic pathogen of humans. In addition to the direct impact of infection, it produces immunosuppressive and carcinogenic aflatoxins. The early detection of A. flavus is therefore necessary to diagnose and monitor fungal infection, to prevent aflatoxin contamination of food and feed, and for effective antifungal therapy. Aspergillus-specific monoclonal antibodies (mAbs) are promising as diagnostic and therapeutic reagents for the tracking and treatment of Aspergillus infections, respectively. However, A. flavus has a complex cell wall composition and dynamic morphology, hindering the discovery of mAbs with well-characterized targets. Here we describe the generation and detailed characterization of mAb5.52 (IgG2aκ) and mAb17.15 (IgG1κ), which bind specifically to the highly immunogenic cell wall antigen A. flavus mannoprotein 1 (Aflmp1). Both mAbs were generated using hybridoma technology following the immunization of mice with a recombinant truncated version of Aflmp1 (ExD, including the homologous CR4 domain) produced in bacteria. We show that mAb5.52 and mAb17.15 bind specifically to A. flavus and A. parasiticus cell wall fragments (CWFs), with no cross-reaction to CWFs from other fungal pathogens. Immunofluorescence microscopy revealed that both mAbs bind to the surface of Aspergillus hyphae and that mAb17.15 also binds to spores. The epitope for both mAbs is localized within the CR4 region of the Aflmp1 protein. These Aspergillus-specific mAbs may be useful for the early detection of fungal infection in food/feed crops, for serodiagnosis in patients with invasive aspergillosis caused by A. flavus infection and for the development of antibody-expressing disease-resistant crops.     

Systematic and validated techniques for the detection of ovarian cancer emphasizing the electro-analytical approach

Ovarian cancer refers to a cancer that forms inside or on the surface of an ovary. It results in the abnormal growth of cells that can attack or spread to other parts of the body. According to the reports, early detection can minimize the risk of mortality and can lead to effective management of the disease. Though, recently used methods can only enable to detect the cancer at an advanced stage. Therefore, rapid and effective approaches for detecting ovarian cancer are urgently in demand. Researchers are fascinating towards an effective portable and early detection technique for the diagnosis of ovarian cancer. Biosensors are best alternative to afore mentioned demand as they are designed for detecting a particular biotic analyte by converting a biological entity such as antibody, blood, cell, etc. into an electronic signal that can be measured and analyzed. Biosensor technology can accommodate rapid and precise diagnosis of cancer-related cells and deliver an improved approach for making them sensitive and specific. Furthermore, choice of biomarkers also plays an important role in determining the stage of cancer. This review summarizes the classification of ovarian cancer, biomarkers and techniques employed for the detection of ovarian cancer. Besides, some of the future outlooks of bio sensing technology are also discussed.     

Adaptive coloration, behavior and predation vulnerability in three juvenile north Pacific flatfishes

Adaptive color change in flatfish has long been of interest to scientists, yet rarely studied from an ecological perspective. Because color change can take a day or so in some species, movement between sediments with differing color or texture may render fish more conspicuous to predators. We conducted laboratory experiments to test the following hypotheses related to adaptive color change in flatfish: 1) fish which do not cryptically match sediment will be more vulnerable to predation, 2) fish will reduce activity and bury to minimize conspicuousness when on a sediment they mismatch, and 3) fish will choose a sediment they match when given a choice. Experiments were conducted using three co-occurring north Pacific juvenile flatfishes: English sole Parophrys vetulus, northern rock sole Lepidopsetta polyxystra and Pacific halibut Hippoglossus stenolepis. As per expectations, juvenile flatfish were more vulnerable to visual predators when they mismatched sediment. Mismatched fish tended to behave differently than fish which matched the sediment. Rather than burying and becoming inactive, they became more active and less likely to bury, perhaps contributing to their predation vulnerability. This increased activity may have represented search for better matching sediment, a stress response, or conspicuousness-related density dependent behavior. Fish which had acclimated to light colored sediment preferred light over dark sediment in choice trials. In contrast, fish acclimated to dark sediment demonstrated no preference. These experiments demonstrate that adaptive coloration is an integral part of the flatfish detection minimization strategy and that movement between habitats can increase risk of predation.     

Early Detection of Pressure Ulcers: Considering the Reperfusion

ObjectivesPressure ulcers are a great handicap for those who develop one. Pressure ulcers can take a long time to heal especially if detected late. These afflictions require a lot of time from the medical personnel and thus a great amount of money. We aim here to check the impact of continuous measurement on the performance of early pressure ulcer detection algorithms.Material and methodsTo detect pressure ulcers early on we use a simulation of a human buttocks to simulate the reaction of it to pressure. This simulation considers the most recent findings about pressure ulcers. In particular, the phenomenon of muscle stiffening when pressure is applied for a long period of time, and the reperfusion phenomenon. We can then simulate pressure captors on the outside interface of the buttocks to use these measurements for detection. We then determine the best threshold on the measured pressures to create standard algorithms that we compare to novel algorithms using an optimized threshold on a calculated damage based on the pressure measurement of the last 2 hours.ResultsWe compare these different algorithms for the early detection of pressure ulcers and show the need to take the measurement variation in time for a better detection. The detection error is improved by 7.3% for balanced classes and 2.7% for a dataset with a majority of healthy buttocks.ConclusionWe showed that taking the evolution of pressure instead of only instantaneous measurement can improve the early detection of pressure ulcer.     

Formation and biological consequences of 5-Formylcytosine in genomic DNA

5-Formyl-2′-deoxycytidine (5fdC) is a naturally occurring nucleobase that is broadly distributed in genomic DNA. 5fdC is produced via the oxidation of 5-methylcytosine (5mdC) by ten-eleven translocation enzyme (TET) and can be further converted to 5-carboxylcytosine (5cadC) by TET. Both 5fdC and 5cadC can be restored to dC by TDG-mediated base excision repair and direct deformylation/decarboxylation. Thus, 5fdC is considered an intermediate in the TET-mediated DNA demethylation pathway. 5fdC also alters the structure and stability of genomic DNA and affects genetic expression. This review summarizes the recent research on 5fdC, detailing its formation, detection and distribution, biological functions and transformation in cells. The challenges and future prospects to further explore the function and metabolism of 5fdC are briefly discussed at the end.     

Immunogold–silver staining-on-a-chip biosensor based on cross-flow chromatography

Immunogold–silver staining (IGSS) was adopted in cross-flow chromatographic analysis in which immunological reactions and silver intensification were sequentially conducted in the vertical and horizontal directions, respectively. Factors controlling the performance, except the silver substrate solution, were optimized to increase the signal-to-background ratio in measurements of cardiac troponin I as a model analyte. In generating the signal, the size of colloidal gold catalyst was critical; the smallest size (5-nm diameter) in the selected range yielded the highest colorimetric signal. To maintain the low background, two processes, blocking the remaining surfaces of membrane after antibody immobilization and washing the residual tracer after immunological reaction, were necessary. Self-nucleation of silver ions also caused a background signal and was controlled to some degree by decreasing the hydrodynamic force that arose when the substrate solution was supplied in the horizontal direction. Finally, a new chip (IGSS-on-a-chip; IOC) that allowed for convenient, efficient IGSS was produced by injection molding of plastic. This method enhanced the detection capability by 51-fold compared to the conventional rapid test kit using 30 nm-sized colloidal gold as the tracer. The IOC biosensor results also showed that silver intensification yield via cross flow after immunological reaction was 19% higher than that by traditional incubation.     

Divergent effects of lure on multi-species camera-trap detections and quality of photos

The use of attractants to increase detection of target species, such as carnivores, in camera trap studies must be tested for its effectiveness and be carefully planned, as it can lead to misleading comparisons among species. We analyzed a five-year multi-species camera trap dataset of lured and control stations in a protected area in the Amazon rainforest. We aimed to identify the lure effect on a wider range of species and assess whether its use is an efficient strategy to increase the number and the quality of carnivore records. From the 14 vertebrate species analyzed, we found that the use of lures had a negligible effect on nine species, and did not improve the number of records or the detection probability of the carnivores. On the other hand, lured stations attracted omnivores and scavengers (common opossum, black-and-white tegu, and turkey vulture) while had the opposite effect on potential prey species (Black-capped capuchin and Northern Amazon squirrel). We detected a stronger effect of the lure when considering the number of records (relative abundance models) than the probability of detection (occupancy models). The lure increased the proportion of high-quality photos, suitable for individual recognition of jaguars, but only for the first weeks, when the lure was fresh. Therefore, we suggest that the sardine and egg-based lures should be refreshed every-two weeks to ensure greater effectiveness in the quality of photos for jaguar individualization. However, it is important to consider that lure renewing will imply a significant increase in field-related costs and it’s likely to bias other species studies. Thus, we advise that lures should only be used if researchers are certain that the focus is only to increase carnivore data at the expense of using non-target species. Camera traps survey design must be carefully planned a priori and the cost-benefit of lure use and refreshment should be weighed in the study context.     

Visual feeding of fish in a turbid environment: Physical and behavioural aspects

Turbidity has both positive and negative effects on prey detection, by increasing or diminishing the contrast between prey and background due to the scattering of light. The positive effect of turbidity on prey contrast depends on the optical properties, scattering properties of suspended particles and the visual sensitivity of the predator.

The positive effect of turbidity is pronounced for larval fish, given that their visual field is short, leaving fewer particles between them and their prey to scatter light and interfere with detection. This relationship, together with a decreased risk of predation, makes turbid environments more optimal for some species and size groups of fish (planktivores and fish larvae) and less so for others (adult piscivore fish). Thus, turbidity might have a structuring effect on a fish community. Recently it has been demonstrated that UV light might have positive effects on prey detection and consumption. How UV light might interact with different kinds of particles producing turbidity is not well documented.     

Density-dependent demography in a Japanese temperate broad-leaved forest

A method of detecting the density-dependent dynamics of a size-structured population is developed. The method is applied to a Japanese broad-leaved forest and the density-dependent and-independent projection matrix models are constructed based on the data of the forest. Then, the difference between the density-independent and density-dependent dynamics is compared in terms of several statistical quantities obtained from the matrices. Three kinds of sensitivity matrices are proposed for the density-dependent matrix model. At earlier stages, the sensitivity when the population density is low are higher than at the equilibrium. On the other hand, the inverse result is obtained at later stages. Moreover, the responses of the forest is analyzed to a decrease in survival rate and to an increase in the probability of gap formation. The decrease in survival rate leads to an extreme decrease in the density of the forest. However, the decrease in recruitment rate gives little effect on it because the effect of density-dependence in recruitment of new individuals is strong. The forest has the optimal rate of gap formation such that leads to the maximum population density.