Recent advances in hydrogen peroxide imaging for biological applications

Mounting evidence supports the role of hydrogen peroxide (H₂O₂) in physiological signaling as well as pathological conditions. However, the subtleties of peroxide-mediated signaling are not well understood, in part because the generation, degradation, and diffusion of H₂O₂ are highly volatile within different cellular compartments. Therefore, the direct measurement of H₂O₂ in living specimens is critically important. Fluorescent probes that can detect small changes in H₂O₂ levels within relevant cellular compartments are important tools to study the spatial dynamics of H₂O₂. To achieve temporal resolution, the probes must also be photostable enough to allow multiple readings over time without loss of signal. Traditional fluorescent redox sensitive probes that have been commonly used for the detection of H₂O₂ tend to react with a wide variety of reactive oxygen species (ROS) and often suffer from photostablilty issues. Recently, new classes of H₂O₂ probes have been designed to detect H₂O₂ with high selectivity. Advances in H₂O₂ measurement have enabled biomedical scientists to study H₂O₂ biology at a level of precision previously unachievable. In addition, new imaging techniques such as two-photon microscopy (TPM) have been employed for H₂O₂ detection, which permit real-time measurements of H₂O₂in vivo. This review focuses on recent advances in H₂O₂ probe development and optical imaging technologies that have been developed for biomedical applications.     

An l-Arginine supplement improves broiler hypertensive response and gut function in broiler chickens reared at high altitude

An experiment was carried out to examine the effects of supplemental dietary arginine (ARG) on growth, hypertensive response, and gut function in broilers reared at high altitude (2,100 m). A total of 120 day-old male broilers (Cobb 500) were divided equally into two treatment groups. Treatments included a control basal diet composed of corn and soybean meal and an experimental diet to which an l-ARG supplement was added at 10 g/kg. The trial lasted for 42 days. There were no treatment differences with regard to feed intake, body weight gain, or feed conversion ratio. However ARG supplementation did increase the plasma concentration of nitric oxide, a potent vasodilator (P?<?0.05), and attenuated indices of pulmonary hypertension as reflected by reductions in the hematocrit and the right to total ventricular weight ratio (P?<?0.05). Significantly enhanced intestinal mucosal development was observed in broilers receiving ARG supplement when compared with controls (P?<?0.05), suggesting that ARG supplementation increased the absorptive surface area of the jejunum and ileum. In conclusion, broiler diets supplemented with ARG beneficially improved pulmonary hemodynamics and appeared to enhance gut function.     

Symplastic and apoplastic uptake and root to shoot translocation of nickel in wheat as affected by exogenous amino acids

This study investigated the effect of exogenous amino acids on apoplastic and symplastic uptake and root to shoot translocation of nickel (Ni) in two wheat cultivars. Seedlings of a bread (Triticum aestivum cv. Back Cross) and a durum wheat cultivar (T. durum cv. Durum) were grown in a modified Johnson nutrient solution and exposed to two levels (50 and 100 μM) of histidine, glycine, and glutamine. Application of amino acids resulted in increasing symplastic to apoplastic Ni ratio in roots of both wheat cultivars, although glutamine and glycine were more effective than histidine under our experimental conditions. The amino acid used in the present study generally increased the relative transport of Ni from the roots to shoots in both wheat cultivars. Higher amounts of Ni were translocated to wheat shoots in the presence of histidine than the other amino acids studied, which indicated that histidine was more effective in translocation of Ni from roots to shoots. Amino acids used in the present study largely increased root symplastic Ni, but shoot Ni accumulation was much lower than the total Ni accumulation in roots, indicating a large proportion of Ni was retained or immobilized in wheat roots (either in the apoplastic or symplastic space), with only a very small fraction of Ni being translocated from the root to the shoot. According to the results, glutamine and glycine were more effective than histidine in enhancing the symplastic to apoplastic Ni ratio in the roots, while more Ni was translocated from the roots to the shoots in the presence of histidine.     

The Effects of Suction and Pin/Lock Suspension Systems on Transtibial Amputees’ Gait Performance

Background

The suction sockets that are commonly prescribed for transtibial amputees are believed to provide a better suspension than the pin/lock systems. Nevertheless, their effect on amputees’ gait performance has not yet been fully investigated. The main intention of this study was to understand the potential effects of the Seal-in (suction) and the Dermo (pin/lock) suspension systems on amputees’ gait performance.

Methodology/Principal Findings

Ten unilateral transtibial amputees participated in this prospective study, and two prostheses were fabricated for each of them. A three-dimensional motion analysis system was used to evaluate the temporal-spatial, kinematics and kinetics variables during normal walking. We also asked the participants to complete some part of Prosthesis Evaluation Questionnaire (PEQ) regarding their satisfaction and problems with both systems. The results revealed that there was more symmetry in temporal-spatial parameters between the prosthetic and sound limbs using the suction system. However, the difference between two systems was not significant (p<0.05). Evaluation of kinetic data and the subjects’ feedback showed that the participants had more confidence using the suction socket and the sockets were more fit for walking. Nevertheless, the participants had more complaints with this system due to the difficulty in donning and doffing.

Conclusion

It can be concluded that even though the suction socket could create better suspension, fit, and gait performance, overall satisfaction was higher with the pin/lock system due to easy donning and doffing of the prosthesis.

Trial Registration

irct.ir IRCT2014012816395N1     

Focus: Antimicrobial Resistance: Brain Abscess Caused by Nocardia asteroides in a Diabetic Patient: A Rare Case Report

Nocardial brain abscess is usually associated with immunodeficiency, but can sometimes emerge in healthy individuals. This infection can be acquired through inhalation or direct inoculation of the bacteria, followed by dissemination to various organs, including the brain, through blood circulation. Mortality rate due to nocardial cerebral abscess is three times higher than that associated with cerebral abscess caused by other types of bacteria. Moreover, patients with Nocardia asteroides-associated brain abscess show poorer prognosis compared to patients with brain abscess caused by other Nocardia species, which is probably due to the high tendency of N. asteroides to become resistant to numerous antibiotics. It is, therefore, of paramount importance to diagnose and treat N. asteroides cerebral abscess in patients as soon as possible. The current paper is a rare report of a brain abscess caused by N. asteroides in a diabetic patient who failed to respond to multiple antibiotics (trimethoprim/sulfamethoxazole and amikacin), but improved by receiving imipenem and linezolid, and was finally successfully treated by surgical operation and long-term antibiotic therapy (imipenem and linezolid).