Objective To investigate the application value of bronchoalveolar lavage fluid(BALF)met-agenomic next-generation sequencing(mNGS)in elderly patients with severe pneumonia.Methods A total of 48 elderly patients with severe pneumonia admitted to the intensive care unit from January to August 2024 were selected and randomly divided into an observation group and a control group,with 24 patients in each group.BALF samples were collected within 24 hours of ICU admission from both groups,with lavage per-formed at the most radiologically evident lesion site.The control group underwent traditional culture at the hospital,while the observation group had one specimen sent for mNGS testing and another specimen subjected to traditional culture at the hospital.Comparison of detection results between mNGS and traditional culture in the observation group,pathogen distribution,infection markers(on days 4 and 7 of ICU admission),and prog-nostic outcomes were compared between the groups.Results The observation group showed higher positive detection rates and higher rates of detecting ≥2 pathogens by mNGS compared to both traditional culture in the same group and the control group(P＜0.05).Excluding Acinetobacter baumannii,Candida albicans,Can-dida glabrata,and Raoultella planticola,the observation group detected higher quantities of fungi,viruses,and rare pathogens than the control group.On days 4 and 7 of ICU admission,the observation group had signifi-cantly lower body temperature,white blood cell count,C reactive protein,and procalcitonin levels compared to the control group(P＜0.05).The observation group also demonstrated shorter ICU stays,reduced mechanical ventilation duration,and total lower hospitalization costs than the control group(P＜0.05).Conclusion BALF mNGS facilitates early identification of mixed and rare pathogens,improves detection rates,broadens microbial coverage,and shortens testing time.

Objective:To explore the effects of vitamin D (VD) on lysosome activity and calcium channel protein Mcoln-1 in hippocampus and cortex of rats after traumatic brain injury (TBI).Methods:Forty-five SD rats were randomly divided into control group (Sham group), TBI model group (TBI group) and calcitriol treatment group (Calcitriol group). TBI models were established by electronic cortical impactor in TBI group and Calcitriol group. The rats in Calcitriol group were given of calitriol (1 μg/kg) by intraperitoneal injection at 30 min, 24 h and 48 h after TBI.Western blot was used to detect the expression of Mcoln-1, LAMP-1 and cathepsin-B in hippocampus and cortex region of rats. Immunofluorescence was used to detect the co-localization of Mcoln-1 and neurons three days later. Morris water maze test was performed on the 8th, 9th and 10th day after surgery in all groups.Results:Morris water maze results showed that compared with sham group((19.54±3.54)s, (18.64±4.63)s, (17.64±5.88)s), the latency of seeking platform escape ((58.75±6.65)s, (50.64±5.56)s, (42.64±5.87)s) were significantly increased in TBI group ( t=18.042, 14.325, 10.117; all P<0.05). On the 8th, 9th and 10th day after modeling, the escape latency of Calcitriol group((44.54±3.75)s, (30.74±4.74)s, (24.43±4.75)s)were significantly lower than those of TBI group ( t=6.539, 8.909, 7.369, all P<0.05). Western blot results showed that the expression of Mcoln-1 in cortex and hippocampus of TBI group were not significantly different from those of Sham group (both P>0.05). Compared with TBI group, the expression of Mcoln-1 protein in cortex and hippocampus of rats in Calcitriol group were significantly increased ( t=18.862, 17.336, both P<0.05). Immunofluorescence showed that the expression of Mcoln-1 and NeuN (neuron marker) co-located in the cortex and hippocampus of rats in the Calcitriol group. Conclusion:VD can improve learning and memory dysfunction after TBI in rats, and its mechanism may be related to the activation of Mcoln-1 calcium channel.

OBJECTIVE：To identify the main unknow impurity of Oxiracetam capsule and determine its content ，so as to improve the standard of quality control. METHODS ：Two-dimensional UPLC -IT-TOF-MS was adopted to qualitatively analyze the unknown impurity. One-dimensional liquid chromatogram analysis was performed on ST PAK C 18 ES column with mobile phase consisted of 0.02 mol/L sodium dihydrogen phosphate solution at the flow rate of 0.5 mL/min. The column temperature was set at 30 ℃，sample size was 20 μL. The detection wavelength was set at 210 nm. Two-dimensional liquid chromatogram analysis was performed on Techmate C 18-STⅡ column with mobile phase consisted of 0.02 mol/L ammonium acetate solution at the flow rate of 0.5 mL/min. The column temperature was 30 ℃. Mass spectrometry was adopted （electropray ionization source ，MS+ and MS － mode data acquisition ）. After the target impurity was located by one-dimensional liquid chromatography ，it was transferred to two-dimensional liquid chromatography-mass spectrometry system for qualitative analysis. The unknown impurity structure was inferred by means of molecular formula prediction module “Accurate Mass Calculator ”in LCMS Solution ，and the refined impurity products by preparation and purification were standardized and confirmed . The impurity content was determined by HPLC （with the same condition of one-dimensional liquid chromatography for qualitative analysis ）. RESULTS ：The main unknown impurity in Oxiracetam capsules is oxiracetam acid. The content of the refined product was 99.5％ after preparation and purification. The contents of oxiracetam acid in 9 batches of Oxiracetam capsules were 0.05％ -0.14％ . CONCLUSIONS ：The established two-dementional UPLC-IT-TOF-MS method can accurately locate the peak position of the impurity oxiracetam acid ，and analyze its structure，while the corresponding content determination method can better separate the impurity from the main drug and other components，with good sensitivity ，precision，repeatability，stability and accuracy. The quality of the finished product of Oxiracetam capsules can be well controlled by using above method .