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ObjectiveTo explore the interaction among root fungi of Stellaria dichotoma var. lanceolata， soil factors， and main components of medicinal materials in lithosol habitats. MethodHigh-throughput sequencing technology was employed to determine the fungal community of the root system of S. dichotoma var. lanceolata at different levels （bulk soil， rhizosphere soil， rhizoplane soil， and root interior） and the soil properties of the root system （bulk and rhizosphere）， and the relationship among the fungal community， soil properties， and the main components of medicinal materials was analyzed. ResultThe total phosphorus， available phosphorus， alkaline nitrogen， dissolved organic carbon， and soil water content in the rhizosphere soil of S. dichotoma var. lanceolata were slightly higher than those in the rhizosphere， but the difference was not significant. Ascomycota is the dominant phylum of root fungi in S. dichotoma var. lanceolata. In the progressive level of bulk-rhizosphere-rhizoplane-root interior system， although the fungal diversity gradually decreased， the abundance of Hypocreales， a new phylum （unclassified_ k_ Fungi）， Helotiales， and Natipusilales gradually increased， among which Hypocreales is the most important fungal group in the root system of S. dichotoma var. lanceolata. The structural equation model （SEM） shows that the physicochemical factors of the root-soil play an important regulatory role in the fungal community and the main components of medicinal herbs， with soil total nitrogen， alkaline nitrogen， soil water content， and pH being the main regulatory factors. Soil nitrogen content is the key to promoting the main components of the medicinal herbs， and Penicillium fungi are the key fungal group to regulate the main components of the medicinal herbs. ConclusionIt highlights that the physicochemical properties of the soil of S. dichotoma var. lanceolata play a crucial role in the fungal community and the components of medicinal materials. Hypocreales fungi in the root of S. dichotoma var. lanceolata were an important group， and Penicillium fungi had a certain role in mediating the components of medicinal materials.
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Objective:To evaluate the prognostic value of arterial lactate (Lac) combined with central venous-to-arterial carbon dioxide difference to arterial-to-central venous oxygen content difference ratio (Pcv-aCO 2/Ca-cvO 2) in patients with septic shock following early fluid resuscitation. Methods:A total of 97 patients with septic shock admitted to intensive care unit (ICU) of Lanzhou University Second Hospital from January 2017 to December 2019 were enrolled. The Pcv-aCO 2/Ca-cvO 2 ratio was calculated from blood gas analysis of radial artery and superior vena cava which was performed before resuscitation and at 6 hours of resuscitation at the same time. The patients were divided into death group and survival group according to the 28-day prognosis. The baseline data, acute physiology and chronic health evaluation Ⅱ (APACHEⅡ) score, sequential organ failure score (SOFA), clinical therapy, lactate clearance rate (LCR) at 6 hours, the length of ICU stay, hemodynamics and oxygen metabolism parameters before and after resuscitation were compared between the two groups. Risk factors were analyzed by multivariate Cox regression for 28-day mortality of patients with septic shock. The receiver operating characteristic (ROC) curve was plotted to assess the prognostic values of these factors for 28-day mortality. Results:① Compared with the survival group, the patients in the death group showed significantly higher levels of APACHEⅡ score (23.96±4.31 vs. 17.70±3.92) and SOFA score (12.74±2.80 vs. 9.23±2.43, both P < 0.01), significantly higher proportions of mechanical ventilation [85.2% (23/27) vs. 50.0% (35/70)] and continuous renal replacement therapy [CRRT; 51.9% (14/27) vs. 25.7% (18/70), both P < 0.05], a significantly more fluid replacement at 6 hours (L: 2.92±0.24 vs. 2.63±0.25, P < 0.01), a significantly lower level of LCR at 6 hours [(11.61±7.76)% vs. (27.67±13.71)%, P < 0.01], and a shorter length of ICU stay (days: 6.37±2.70 vs. 7.67±2.31, P < 0.05). ② Compared with the survival group, the patients before resuscitation in the death group showed a significantly lower level of mean arterial pressure [MAP (mmHg, 1 mmHg = 0.133 kPa): 52.63±4.35 vs. 55.74±3.01, P < 0.01], significantly higher levels of Lac and Pcv-aCO 2/Ca-cvO 2 ratio [Lac (mmol/L): 7.13±1.75 vs. 5.22±1.36, Pcv-aCO 2/Ca-cvO 2 ratio: 1.67±0.29 vs. 1.48±0.22, both P < 0.01]; and the patients at 6 hours of resuscitation in the death group showed a significantly lower level of MAP (mmHg: 62.59±4.80 vs. 66.71±3.91, P < 0.01), significantly higher levels of central venous pressure (CVP), Lac, Pcv-aCO 2 and Pcv-aCO 2/Ca-cvO 2 ratio [CVP (mmHg): 10.74±1.40 vs. 8.80±0.75, Lac (mmol/L): 6.36±1.86 vs. 3.90±1.95, Pcv-aCO 2 (mmHg): 7.59±2.02 vs. 4.34±1.37, Pcv-aCO 2/Ca-cvO 2 ratio: 1.87±0.51 vs. 1.03±0.27, all P < 0.01]. ③ Multivariate Cox regression analysis showed that the independent risk factors for 28-day mortality in patients with septic shock were Lac and Pcv-aCO 2/Ca-cvO 2 ratio whether before or at 6 hours of resuscitation [Lac before resuscitation: relative risk ( RR) = 1.434, 95% confidence interval (95% CI) was 1.070-1.922, P = 0.016; Lac at 6 hours of resuscitation: RR = 1.564, 95% CI was 1.202-2.035, P = 0.001; Pcv-aCO 2/Ca-cvO 2 ratio before resuscitation: RR = 2.828, 95% CI was 1.108-4.207, P = 0.038; Pcv-aCO 2/Ca-cvO 2 ratio at 6 hours of resuscitation: RR = 4.386, 95% CI was 2.842-5.730, P = 0.000]. ④ ROC curve analysis showed that Lac and Pcv-aCO 2/Ca-cvO 2 ratio at 6 hours of resuscitation had predictive value for the prognosis of patients with septic shock, the area under ROC curve (AUC) was 0.849 (95% CI was 0.762-0.914) and 0.905 (95% CI was 0.828-0.955), respectively. However, the predictive value of Lac combined with Pcv-aCO 2/Ca-cvO 2 ratio in patients with septic shock was significantly higher than Lac [AUC (95% CI): 0.976 (0.923-0.996) vs. 0.849 (0.762-0.914), Z = 3.354, P = 0.001], the sensitivity was 97.14%, and the specificity was 88.89%. Conclusions:Lac and Pcv-aCO 2/Ca-cvO 2 ratio are independent risk factors for predicting 28-day mortality in patients with septic shock. Lac combined with Pcv-aCO 2/Ca-cvO 2 ratio can assess the prognosis of patients with septic shock more accurately.