Erythropoietin improve spatial memory impairment following methamphetamine neurotoxicity by inhibition of apoptosis, oxidative stress and neuroinflammation in CA1 area of hippocampus.

OBJECTIVE: Methamphetamine (METH) is one of the most widely used addictive drugs, and addiction to it is on the rise all over the world. METH abuse has long-term damaging effects that reduce memory and impair cognitive functions. According to studies, the observed effects are strongly related to the nerve cell damage caused by METH, which leads to neurotoxicity. Some of these intra-neuronal events include dopamine oxidation, excitotoxicity, and oxidative stress. Erythropoietin (EPO) is a hormone produced primarily by the kidneys and, in small quantities, by the liver. Studies have shown that EPO exhibits considerable neuroprotective effects. This study aimed to investigate the protective effects of EPO on METH neurotoxicity. METHODS: Initially, 48 male Wistar rats, weighing 250-300 g, were randomly assigned to four groups: control (n = 12), METH (n = 12), and METH+EPO (2500, 5000 IU/kg/IP- n = 12). METH was injected intraperitoneally at a dose of 40 mg per kg of body weight (four injections of 10 mg every two hours) to induce neurotoxicity. EPO was injected at doses of 2500 and 5000 IU/kg seven days after the last METH administration (ip). Morris water maze test was performed following EPO injection (1 day after the last dose) to assess spatial memory. The brains were removed after the behavioral test, biochemical evaluations and immunohistochemistry (caspase-3 and GFAP) was performed. RESULTS: The results showed that EPO treatment significantly improved spatial memory impairment (P < 0.01), compared to the METH group, EPO was a significant reduction in malondialdehyde and TNF-α (P < 0.01), as well as an increase in superoxide dismutase (P < 0.05) and glutathione-PX (P < 0.01). Furthermore, EPO treatment significantly reduced the number of GFAP positive cells (P < 0.01) and caspase 3 (P < 0.001) in the hippocampus (CA1 region). CONCLUSIONS: The study findings suggested that EPO may have great neuroprotective effects on METH neurotoxicity due to its anti-inflammatory, antioxidant, and antiapoptotic properties.

A spectroscopic study on the absorption of carbonic anhydrase onto the nanoporous silica nanoparticle.

Herein, KIT-6 nanoporous silica nanoparticles were used as a solid support for immobilization of bovine carbonic anhydrase, isoform II (BCA II). The zeta potential study revealed that KIT-6 and BCA II provided negative (-13.58±1.95mV) and positive (4.23±0.72mV) charge distribution, respectively. Dynamic light scattering (DLS) analysis also showed that the hydrodynamic radius of KIT-6 is less than 100nm. In addition, the structural studies of free and immobilized BCA II against urea-induced denaturation were investigated by circular dichroism (CD) and fluorescence spectroscopy. CD studies showed that the absorbed BCA II, in comparison with the free enzyme, demonstrated higher stability against rising urea concentration. Fluorescence spectroscopy showed lower values of Stern- Volmer constant (KSV) for immobilized BCA II relative to free enzyme, reflecting the relative enzyme stability of BCA II after immobilization. Melting temperature (Tm) measurement of free and immobilized BCA II showed that immobilized enzyme had a more stable structure (Tm=71.9°C) relative to the free counterpart (Tm=64.7°C). In addition, the immobilized BCA II showed pronounced stability against pH and thermal deactivation. This study may provide new and complementary details regarding the design and development of enzymes in industrial applications.

Can flap design influence the incidence of alveolar osteitis following removal of impacted mandibular third molars?

This study sought to evaluate the influence of flap design (that is, modified triangular flap or buccal envelope flap) on alveolar osteitis (AO) and on healing following the surgical removal of an impacted mandibular third molar. A double-blind split-mouth clinical trial examined 17 patients who were candidates for extraction of a bilaterally impacted mandibular third molar with the same difficulty index; a modified triangular flap was placed on one side and a buccal envelope flap (control) was placed on the other side. AO and healing were assessed at three and seven days after surgery. Data were analyzed with the McNemar and Wilcoxon signed-rank tests. The modified triangular flap decreased the incidence of AO and expedited healing at seven days postsurgery. In addition, statistically significant differences were observed in terms of both AO and postoperative healing.