Increased apoptosis in human knee osteoarthritis cartilage related to the expression of protein kinase B and protein kinase Cα in chondrocytes

Protein kinase B (Akt) and protein kinase Cα (PKCα) play important roles in the regulation of cell apoptosis. The aim of this study was to investigate the expression of Akt and PKCa in chondrocytes of human knee osteoarthritic (OA) cartilage, further evaluating their role in chondrocyte apoptosis during OA progression. Human knee OA cartilages were obtained from 38 patients undergoing knee arthroplasty, which is the medium-late stage of OA. Healthy knee cartilages were obtained from 11 amputees. The samples taken from the condyle of femur were collected routinely for morphological, immunohistochemical and Western blot detection, respectively. Light microscopy and laser-scanning confocal microscopy were used for morphological observation. The optical density with computer image analysis evaluated the intensity of immunohistochemical reaction of Akt and PKCα in OA cartilage. Western blot detected the protein expression levels. The results indicated that Akt and PKCa were involved in OA progression, along with the increase of cell apoptosis. In OA cartilage, Akt decreased (p < 0.05) and PKCα increased (p < 0.05). There was a negative correlation and interaction between Akt and PKCα (r = –0.8). These results demonstrated that both Akt and PKCα are related to increased chondrocyte apoptosis in human OA cartilage. The correlation between human OA progression, the role of Akt and PKCα, and chondrocyte apoptosis allows for new therapeutic strategies to be considered

2-(5-Amino-2H-tetra­zol-2-yl)acetic acid

In the title mol­ecule, C3H5N5O2, the tetra­zole ring and carboxyl group form a dihedral angle of 82.25 (14)°. In the crystal, adjacent mol­ecules are linked through O—H⋯N, N—H⋯O and N—H⋯N hydrogen bonds into layers parallel to the bc plane

Coronal condensations caused by magnetic reconnection between solar coronal loops

Employing Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) multi-wavelength images, we report the coronal condensation during the magnetic reconnection (MR) between a system of open and closed coronal loops. Higher-lying magnetically open structures, observed in AIA 171 A images above the solar limb, move downward and interact with the lower-lying closed loops, resulting in the formation of dips in the former. An X-type structure forms at the interface. The interacting loops reconnect and disappear. Two sets of newly-reconnected loops then form and recede from the MR region. During the MR process, bright emission appears sequentially in the AIA 131 A and 304 A channels repeatedly in the dips of higher-lying open structures. This indicates the cooling and condensation process of hotter plasma from ~0.9 MK down to ~0.6 MK, and then to ~0.05 MK, also supported by the light curves of the AIA 171 A, 131 A, and 304 A channels. The part of higher-lying open structures supporting the condensations participate in the successive MR. The condensations without support by underlying loops then rain back to the solar surface along the newly-reconnected loops. Our results suggest that the MR between coronal loops leads to the condensation of hotter coronal plasma and its downflows. MR thus plays an active role in the mass cycle of coronal plasma because it can initiate the catastrophic cooling and condensation. This underlines that the magnetic and thermal evolution has to be treated together and cannot be separated, even in the case of catastrophic cooling.Comment: 10 pages, 6 figure

Gastro-protective actions of Aloe barbadensis Miller mitigate ethanol-induced gastric injury in rats

Purpose: To investigate the gastroprotective effect of leaf extract of Aloe barbadensis on ethanolinduced gastric ulcer in rats.Methods: Healthy male Wistar rats (n = 30) weighing 180 - 220 g (mean weight = 200 ± 20 g) were randomly assigned to 6 groups (5 rats/group): control group, gastric ulcer group, two Aloe barbadensis extract groups (250 and 500 mg/kg), cimetidine group and indomethacin group. Gastric ulcer was induced via oral injection of absolute ethanol at a dose of 1 mL/kg after a 24-h fast. Gross evaluation, determination of gastric juice acidity and histological examination of gastric tissue were carried out.Results: Treatment of gastric ulcer rats with Aloe barbadensis extract significantly reduced ulcerated area (UA), ulcer index (UI), and acidity of gastric juice (p < 0.05). Injection of 1 % carrageenan into rat hind paw led to a time-dependent increase in paw volume which peaked 3 h after injection. However, the Aloe barbadensis extract significantly and dose-dependently reduced the volume of inflamed paw, and inhibited edema formation (p < 0.05). It also markedly reduced or completely eliminated edema and leucocyte infiltration. Moreover, treatment of gastric ulcer rats with Aloe barbadensis leaf extract led to significant and dose-dependent reduction in gastric tissue MDA level (p < 0.05). Histological examination of the gastric wall showed that control rats had severe injury in gastric mucosa,accompanied by edema and leucocytes infiltration, relative to rats pretreated with extract which showed marked gastric protection and inhibition of edema and leucocytes infiltration. Moreover, the extract treatment protected the gastric surface against ulceration as indicated by reduced lesions in the treated rat model.Conclusion: These results show that Aloe barbadensis mitigates ethanol-induced gastric injury in rats via inhibition of lipid  peroxidation and inflammation. Thus, the extract has potentials for development into a therapeutic agent for the management of  gastric ulcer. Keywords: Aloe barbadensis, Gastric ulcer, Gastric mucosa, Inflammation, Lipid peroxidatio