Platelet formation is the consequence of caspase activation within megakaryocytes

Platelets are formed from mature megakaryocytes (MKs) and arise from the development of long and thin cytoplasmic extensions called proplatelets. After platelet release, the senescent MKs (nucleus surrounded by some cytoplasm) undergo cell death by apoptosis. To explore the precise role of apoptosis in proplatelet formation, we grew human MKs from CD34(+) cells and assessed the possible role of caspases. Proteolytic maturation of procaspase-3 and procaspase-9 was detected by immunoblots in maturing MKs as well as in proplatelet-bearing MKs and senescent MKs. Cleavage of caspase substrates such as gelsolin or poly adenosine diphosphate (ADP)-ribose polymerase (PARP) was also detected. Interestingly, activated forms of caspase-3 were detected in maturing MKs, before proplatelet formation, with a punctuate cytoplasmic distribution, whereas a diffuse staining pattern was seen in senescent and apoptotic MKs. This localized activation of caspase-3 was associated with a mitochondrial membrane permeabilization as assessed by the release of cytochrome c, suggesting an activation of the intrinsic pathway. Moreover, these MKs with localized activated caspase-3 had no detectable DNA fragmentation. In contrast, when apoptosis was induced by staurosporine, diffuse caspase activation was seen; these MKs had signs of DNA fragmentation, and no proplatelet formation occurred. The pan-caspase inhibitor z-VAD.fmk as well as more specific inhibitors of caspase-3 and caspase-9 blocked proplatelet formation, whereas an inhibitor of calpeptin had no effect. Overexpression of Bcl-2 also inhibited proplatelet formation in maturing MKs. Thus, localized caspase activation is causal to proplatelet formation. We conclude that proplatelet formation is regulated by a caspase activation limited to only some cellular compartments.     

Paradox in the cubital tunnel syndrome—frequent involvement of left elbow: first report

Objective

Cubital tunnel syndrome (CuTS) is the second most common compression neuropathy in the arm, but the existence of a compressive cause has not been determined conclusively and the majority of the cases are idiopathic. In this paper, involvement sides of limbs of patients with cubital tunnel syndrome were studied.

Material and methods

Between October 2008 and December 2011, the clinical assessment of consecutive operated patients with cubital tunnel syndrome in Rize Education and Research Hospital were analysed. The diagnosis and severity of syndrome was based on electro-diagnostic study.

Results

This study included 57 consecutive patients with cubital tunnel syndrome (39 men, 18 women; mean age, 44,7 years; range, 23–79 years; mean age, 44,7 years; range, 23–79 years); 31 patients underwent surgical treatment. Involvement was on the right side in 18 and on the left in 39 patients. Severity scores and MCV were statistically significant between sides.

Conclusion

Profound involvement with cubital tunnel was found in left elbow. According to the finding of non-dominant elbow involvement in our study, the exact etiology and ideal management of cubital tunnel syndrome continues to be heavily debated.     

Bilirubin and its oxidation products damage brain white matter

Brain injury after intracerebral hemorrhage (ICH) occurs in cortex and white matter and may be mediated by blood breakdown products, including hemoglobin and heme. Effects of blood breakdown products, bilirubin and bilirubin oxidation products, have not been widely investigated in adult brain. Here, we first determined the effect of bilirubin and its oxidation products on the structure and function of white matter in vitro using brain slices. Subsequently, we determined whether these compounds have an effect on the structure and function of white matter in vivo. In all, 0.5 mmol/L bilirubin treatment significantly damaged both the function and the structure of myelinated axons but not the unmyelinated axons in brain slices. Toxicity of bilirubin in vitro was prevented by dimethyl sulfoxide. Bilirubin oxidation products (BOXes) may be responsible for the toxicity of bilirubin. In in vivo experiments, unmyelinated axons were found more susceptible to damage from bilirubin injection. These results suggest that unmyelinated axons may have a major role in white-matter damage in vivo. Since bilirubin and BOXes appear in a delayed manner after ICH, preventing their toxic effects may be worth investigating therapeutically. Dimethyl sulfoxide or its structurally related derivatives may have a potential therapeutic value at antagonizing axonal damage after hemorrhagic stroke.     

Colour Change of Sustainable Concrete Containing Waste Ceramic and Hybrid Fibre: Effect of Temperature

Construction and demolition (C&D) waste was considered as zero value materials and, as a result, most C&D waste materials ended up in landfills, eventually constituting environmental issues. Therefore, it is important to explore the potential of such C&D waste materials for concrete production. Thus, this research effort aims to find a new method to improve sustainable concrete properties exposed to elevated temperatures at the lowest costs and identify the relationship between temperature change and a change in colour in a heat-exposed concrete structure. Therefore, this study explored the behaviour of three types of concrete: plain concrete (PC), waste ceramic optimal concrete (WOC), and waste ceramic optimal concrete reinforced by hybrid fibre (WOC-Hybrid) in ambient and elevated temperature. The study shows that colour change in a concrete structure exposed to high temperature has a consistent relationship, where it has been found that the colour alteration is of great interest because its appearance usually coincides with the onset of a significant loss of concrete strength as a result of elected temperatures. Overall, it can be considered that waste ceramic materials reinforced by hybrid fibres can be used for concrete production, and by doing so, the negative impact of these wastes on the environment can be controlled as well as fortify the mechanical properties.     

Solution combustion synthesis of Ni-based hybrid metal oxides for oxygen evolution reaction in alkaline medium

Oxygen evolution reaction (OER) has arisen as an outstanding technology for energy generation, conversion, and storage. Herein, we investigated the synthesis of nickel-based hybrid metal oxides (Ni_xM_1−xO_y) and their catalytic performance towards OER. Ni_xM_1−xO_y catalysts were synthesized by solution combustion synthesis (SCS) using the metal nitrates as oxidizer and glycine as fuel. Scanning electron microscope (SEM) micrographs display a porous morphology for the hybrid binary Ni_xM_1−xO_y, the common feature of combusted materials. X-ray diffraction (XRD) of Ni_xM_1−xO_y depicted well-defined diffraction peaks, which confirms the crystalline nature of synthesized catalysts. The particle size of as-synthesized materials ranges between 20 and 30 nm with a mesoporous nature as revealed by N₂-physisorption. The electrocatalytic performance of the as-prepared materials was evaluated towards OER in alkaline medium. Among them, Ni_xCo_1−xO_y showed the best catalytic performance. For instance, it exhibited the lowest overpotential at a current density of 10 mA cm⁻² (404 mV), onset potential (1.605 V), and Tafel slope (52.7 mV dec⁻¹). The enhanced electrocatalytic performance of Ni_xCo_1−xO_y was attributed to the synergism between cobalt and nickel and the alteration of the electronic structure of nickel. Also, Ni_xCo_1−xO_y afforded the highest Ni³⁺/Ni²⁺ when compared to other electrocatalysts. This leads to higher oxidation states of Ni species, which promote and improve the electrocatalytic activity.

Ni-based mixed transition metal oxides (MTMO) (Ni_xM_1−xO_y) were synthesized using the solution combustion synthesis (SCS), and investigated as electrocatalysts towards oxygen evolution reaction (OER) in alkaline medium.     

Fabrication and Characterization of Highly Efficient As-Synthesized WO3/Graphitic-C3N4 Nanocomposite for Photocatalytic Degradation of Organic Compounds

The incorporation of tungsten trioxide (WO₃) by various concentrations of graphitic carbon nitride (g-C₃N₄) was successfully studied. X-ray diffraction (XRD), Scanning Electron Microscope (SEM), and Diffused Reflectance UV-Vis techniques were applied to investigate morphological and microstructure analysis, diffused reflectance optical properties, and photocatalysis measurements of WO₃/g-C₃N₄ photocatalyst composite organic compounds. The photocatalytic activity of incorporating WO3 into g-C₃N₄ composite organic compounds was evaluated by the photodegradation of both Methylene Blue (MB) dye and phenol under visible-light irradiation. Due to the high purity of the studied heterojunction composite series, no observed diffraction peaks appeared when incorporating WO₃ into g-C₃N₄ composite organic compounds. The particle size of the prepared composite organic compound photocatalysts revealed no evident influence through the increase in WO₃ atoms from the SEM characteristic. The direct and indirect bandgap were recorded for different mole ratios of WO₃/g-C₃N_4, and indicated no apparent impact on bandgap energy with increasing WO₃ content in the composite photocatalyst. The composite photocatalysts’ properties better understand their photocatalytic activity degradations. The pseudo-first-order reaction constants (K) can be calculated by examining the kinetic photocatalytic activity.