The important and diverse regulatory roles of Ca(2+) in eukaryotes are conveyed by the EF-hand containing calmodulin superfamily. However, the calcium-regulatory proteins in prokaryotes are still poorly understood. In this study, we report the three-dimensional structure of the calcium-binding protein from Streptomyces coelicolor, named CabD, which shares low sequence homology with other known helix-loop-helix EF-hand proteins. The CabD structure should provide insights into the biological role of the prokaryotic calcium-binding proteins. The unusual structural features of CabD compared with prokaryotic EF-hand proteins and eukaryotic sarcoplasmic calcium-binding proteins, including the bending conformation of the first C-terminal α-helix, unpaired ligand-binding EF-hands and the lack of the extreme C-terminal loop region, suggest it may have a distinct and significant function in calcium-mediated bacterial physiological processes, and provide a structural basis for potential calcium-mediated regulatory roles in prokaryotes.
Amino Acid Sequence ; Binding Sites ; Calcium ; physiology ; Calcium-Binding Proteins ; chemistry ; Crystallography, X-Ray ; EF Hand Motifs ; Molecular Sequence Data ; Protein Binding ; Protein Structure, Tertiary ; Sequence Alignment ; Sequence Homology, Amino Acid ; Streptomyces coelicolor ; Structural Homology, Protein ; Surface Properties

Perioperative cardiac arrest is a significant cause of perioperative mortality in patients.The first clinical practice recommendation dedicated to the management of perioperative cardiac arrest was published in 2021 and contains 22 specific recommendations.This clinical practice recommendation includes indicators to monitor during treatment, the sequence of defibrillation and chest compressions, the use of epinephrine and antiarrhythmic drugs, treatment strategies for specific types of perioperative cardiac arrest, the use of adjunctive therapies such as ultrasound to assist in treatment, setting appropriate hemodynamic and respiratory parameters, and temperature management.This clinical practice recommendation is essential for effective management of perioperative cardiac arrest and will also provide guidance for further exploration of the management of perioperative cardiac arrest in the future.

Objective: To compare the in vitro biocompatibility of bone marrow mesenchymal cells on polyetheretherketone (PEEK) and titanium (Ti) surfaces. Methods : PEEK and Ti foils with thicknesses of 1 mm and diameters of 10 mm were prepared. First, bone marrow mesenchymal cells were separated and purified by the whole bone marrow adherent culture method in vitro. Then, osteogenesis-induced bone marrow mesenchymal cells were cultivated on the surfaces of the PEEK and Ti foils. Scanning electron microscopy (SEM), the Alamar Blue test, an alkaline phosphatase (ALP) kit and Alizarin Red staining were used to analyze calcium nodules and compare the adhesion, proliferation and osteogenic differentiation ability of bone marrow mesenchymal cells on the surfaces of the PEEK and Ti foils. Results : ① The morphology of the bone marrow mesenchymal cells cultured on the PEEK and Ti foils at 1 h, 4 h and 24 h showed no significant differences. ② In the 1 h, 3 h, 1 d and 3 d cultures of the bone marrow mesenchymal cells inoculated on the surfaces of the foils, the number of living cells in the PEEK group was greater than that in the Ti group (P < 0.05). ③ In the 7 d and 14 d osteogenesis-induced cultures of the inoculated bone marrow mesenchymal cells, the ALP activity of the PEEK group cells was significantly greater than that of the Ti group cells (P < 0.05). ④ Semiquantitative analysis after Alizarin Red staining showed that the mineralization degree of the bone marrow mesenchymal cells induced by osteoblasts was greater in the PEEK group than in the Ti group (P < 0.05). Conclusion PEEK has better in vitro biocompatibility than Ti and can better promote cell adhesion, proliferation and osteogenic differentiation compared with Ti, and so it is expected to become a new dental implant material.

Objective: To investigate the efficacy and safety of IA regimen which contains idarubicin (IDA) 8 mg/m², 10 mg/m² or 12 mg/m² as induction chemotherapy for adult patients with de-novo acute myeloid leukemia (AML) . Methods: A total of 1 215 newly diagnosed adult AML patients, ranging from May 2011 to March 2015 in the First Affiliated Hospital of Soochow University and other 36 clinical blood centers in China were enrolled in the multicenter, single-blind, non-randomized, clinical controlled study. To compare the response rate of complete remission (CR) , adverse events between different dose idarubicin combined with cytarabine (100 mg/m²) as induction chemotherapy in newly diagnosed patients of adult AML. Results: Of 1 207 evaluable AML patients were assigned to this analysis of CR rate. The CR rates of IDA 8 mg/m² group, IDA 10 mg/m² group and IDA 12 mg/m² group were 73.6% (215/292) , 84.1% (662/787) and 86.7% (111/128) , respectively (P<0.001) . After adjusted for age, blast ratio of bone marrow, FAB classification and risk stratification, the odds ratios (95% CI) of IDA 10 mg/m² group and IDA 12 mg/m² group were 0.49 (0.34-0.70) and 0.36 (0.18-0.71) , as compared with the IDA 8 mg/m² group (P<0.001, P=0.003) . In the intermediate and favorable groups, CR rates was 76.5% (163/213) , 86.9% (506/582) and 86.1% (68/79) in different doses of IDA (P=0.007) . Interestingly, IA regimen with IDA 10 mg/m² was the only beneficial factor affecting CR in this group after adjusted for age, blast ratio of bone marrow and FAB classification[OR=0.47 (95% CI 0.31-0.71) , P<0.001]. CR rates in adverse group was 50.0% (18/36) , 60.6% (43/71) and 81.8% (18/22) respectively (P=0.089) . However, the odds ratios (95% CI) of IDA 12 mg/m² when compared with the IDA 8 mg/m² was 0.22 (0.06-0.80) , after adjusted for age, blast ratio of bone marrow and FAB classification. The median time (days) of neutrophil count less than 0.5×10⁹/L in IDA 8 mg/m² group, IDA 10 mg/m² group and IDA 12 mg/m² group were 14 (11-18) , 15 (11-20) and 18 (14-22) , respectively (P=0.012) and of platelet count lower than 20×10⁹/L were 14 (7-17) , 15 (11-20) and 17 (15-21) , respectively (P=0.001) . The incidences of lung infection in the three groups were 9.8%, 13.5% and 25.2%, respectively (P<0.001) . Conclusions For young adult patients (aged 18-60 years) with AML in China, intensifying induction therapy with idarubicin 10 mg/m² is clinically superior to IDA 8 mg/m² and IDA 12 mg/m² in favorable intermediate AML subgroup. However, idarubicin 12 mg/m² is more suitable to adverse AML subgroup.