A prognostic scoring system for operated acute epidural hematoma based on gray-white matter ratio.

ABSTRACT: To determine the prognostic risk factors of patients with acute epidural hematoma (AEDH), a scoring system was established based on gray-white matter ratio (GWR) and internal verification was performed.All patients with AEDH who underwent surgical treatment in Qinghai Provincial People's Hospital from January 2013 to June 2019 were continuously collected. The clinical and imaging data of the patients were collected. According to Glasgow Outcome Scale at 3 months after operation, the patients were divided into poor and good prognosis groups, respectively. The GWR value of the nonhematoma side was measured at the inner capsule area. Univariate and multivariate analyses were used. Independent predictors significantly related to the prognosis of AEDH were screened out and a nomogram was established based on these factors.A total of 170 cases were included in this study, the Glasgow Coma Score (severe and moderate), cerebral hernia, midline shift, preoperative GWR, postoperative GWR, hematoma thickness/midline shift, time from coma to surgery, and decompression of bone flap were the independent risk factors for predicting the poor prognosis of AEDH. Moreover, the prediction ability of nomogram was higher than any other independent predictive factors.The nomogram model established represents the most effective factor to predict the prognosis of operated AEDH. The scoring system is characterized by high accuracy, simplicity and feasibility, with a wide range of clinical application prospects.

Expression of secreted His-tagged S-adenosylmethionine synthetase in the methylotrophic yeast Pichia pastoris and its characterization, one-step purification, and immobilization.

S-Adenosylmethionine synthetase (SAM synthetase) catalyzes the synthesis of S-adenosylmethionine (SAM), which plays an important role in cellular functions such as methylation, sulfuration, and polyamine synthesis. To develop a simple and effective way to enzymatically synthesize and produce SAM, a soluble form of SAM synthetase encoded by SAM2 from Saccharomyces cerevisiae was successfully produced at high level ( approximately 200 mg/L) by the recombinant methylotrophic yeast Pichia pastoris. The secreted His6-tagged SAM synthetase was purified in a single chromatography step with a yield of approximately 82% for the total activity. The specific activity of the purified synthetase was 23.84 U/mg. The recombinant SAM synthetase could be a kind of allosteric enzyme with negative regulation. The enzyme functioned optimally at a temperature of 35 degrees C and pH 8.5. The stability of the recombinant synthetase and the effectiveness of different factors in preventing the enzyme from inactivation were also studied. Additional experiments were performed in which the recombinant SAM synthetase was purified and immobilized in one step using immobilized metal-chelate affinity chromatography. The immobilized synthetase was found to be 40.4% of the free enzyme activity in catalyzing the synthesis of SAM from dl-Met and ATP.