Genetically encoded Ca(2+) indicators (GECI) are important for the measurement of Ca(2+) in vivo. GCaMP2, a widely-used GECI, has recently been iteratively improved. Among the improved variants, GCaMP3 exhibits significantly better fluorescent intensity. In this study, we developed a new GECI called GCaMPJ and determined the crystal structures of GCaMP3 and GCaMPJ. GCaMPJ has a 1.5-fold increase in fluorescence and 1.3-fold increase in calcium affinity over GCaMP3. Upon Ca(2+) binding, GCaMP3 exhibits both monomeric and dimeric forms. The structural superposition of these two forms reveals the role of Arg-376 in improving monomer performance. However, GCaMPJ seldom forms dimers under conditions similar to GCaMP3. St ructural and mutagenesis studies on Tyr-380 confirmed its importance in blocking the cpEGFP β-barrel holes. Our study proposes an efficient tool for mapping Ca(2+) signals in intact organs to facilitate the further improvement of GCaMP sensors.
Calcium ; chemistry ; metabolism ; Calmodulin ; chemistry ; genetics ; metabolism ; Crystallography, X-Ray ; Dimerization ; Green Fluorescent Proteins ; chemistry ; genetics ; metabolism ; Histidine ; chemistry ; genetics ; metabolism ; Hydrogen-Ion Concentration ; Myosin-Light-Chain Kinase ; chemistry ; genetics ; metabolism ; Peptide Fragments ; chemistry ; genetics ; metabolism ; Protein Structure, Tertiary ; Recombinant Fusion Proteins ; biosynthesis ; chemistry ; genetics

Objective:To study the use of temporary abdominal closure combined with continuous negative pressure drainage in management of patients with severe pancreatic trauma.Methods:A retrospective analysis was conducted on the data of 33 patients with severe pancreatic trauma treated at the 908th Hospital of the Joint Logistics Support Force of PLA from June 2014 to June 2020. There were 28 males and 5 females, with an average age of 43.1 years. Sixteen patients were treated with temporary abdominal closure combined with continuous negative pressure drainage (the combined group), and 17 patients with direct abdominal closure and traditional drainage (the control group). The body temperature, heart rate, intra-abdominal pressure, length of hospital stay and postoperative complications were compared between groups.Results:There was no significant difference in the preoperative intra-abdominal pressure between the two groups ( P>0.05). The intra-abdominal pressure on the first, second and third postoperative days in the combined group were (11.7±2.6) mmHg (1 mmHg=0.133 kpa), (11.1±3.2) mmHg and (10.2±3.7) mmHg respectively, which were significantly lower than those in the control group of (18.1±5.3) mmHg, (15.6±6.2) mmHg, and (15.0±6.7) mmHg, respectively (all P<0.05). The total in-hospital and ICU stays in the combined group were (29.2±17.8) days and (7.1±3.2) days respectively, which were significantly less than those in the control group of (49.5±26.3) days and (11.8±7.6) days (both P<0.05). The decreases in body temperature and heart rate in the combined group were (-0.1±0.9)℃ and (18.2±17.2) times/min respectively, which were significantly more than those in the control group of (-1.2±0.7)℃ and (-5.9±17.2) times/min respectively (both P<0.05). The incidence of postoperative complication in the combined group was 18.8% (3/16), which was significantly lower than that in the control group of 52.9% (9/17)(χ 2=4.164, P=0.041). Conclusion:Significant advantages were obtained by using temporary abdominal closure combined with continuous negative pressure drainage to treat patients with severe pancreatic trauma. There were significantly lower abdominal pressure, less abdominal complications, and shorter hospital and ICU stays. This treatment is worthy of promotion in management of patients with severe pancreatic trauma.

Objective To investigate the clinicopathological significance of PDC in liver metastases and analyze the correlation of PDC between liver metastases and primary lesions. Methods Retrospective analysis of 72 matched cases of colorectal cancer with liver metastases was performed. The PDC in primary tumor and liver metastatic lesion was interpreted synchronously, and then the relationship between PDC in liver metastasis and clinicopathological parameters was analyzed based on the correlation of PDC between primary and metastatic lesions. In addition, PDC were interpreted in accordance with Uenos' standard. Results Among the 72 cases of liver metastasis of colorectal cancer, the number of G1, G2, and G3 graded by PDC was 28, 24, and 20, respectively. The PDC in liver metastatic lesion was correlated with tumor budding in liver metastatic lesion and PDC grade of primary lesion. No significant correlation with the size and number of liver metastatic lesion, the site, WHO grade, depth of invasion, lymph node metastasis, vascular invasion or tumor budding of the primary lesion was observed. Conclusion A positive correlation is found between liver metastasis of colorectal adenocarcinoma and PDC grade of primary tumor. Evaluating the PDC grade of primary tumor may provide a reference for the risk of liver metastasis.