Association between active cytomegalovirus infection and lung fibroproliferation in adult patients with acute respiratory distress syndrome: a retrospective study.

BACKGROUND: Cytomegalovirus (CMV) has high seroprevalence, and its active infection is associated with several adverse prognoses in adult patients with acute respiratory distress syndrome (ARDS). However, the role of active CMV infection in ARDS-associated fibroproliferation is unknown. This study aimed at determining the association between active CMV infection and lung fibroproliferation in adult patients with ARDS. METHODS: We retrospectively reviewed the medical records of all adult patients with ARDS who were admitted to the intensive care unit (ICU) from January 2018 to December 2020 at a national university-affiliated hospital in China. Study subjects were divided into active and non-active CMV infection groups based on CMV DNAemia within a 28-day ICU hospitalization. Lung fibroproliferation was measured using chest high-resolution computed tomography (HRCT) and N-terminal peptide of serum procollagen III (NT-PCP-III) within the first 28 days of ICU admission. Pulmonary fibrosis, clinical features, laboratory findings, treatment measures, and clinical outcomes were compared between the two groups. RESULTS: Among the 87 ARDS patients included in this study, the incidence of active CMV infection was 16.1% within the 28-day ICU admission period. In logistic regression analyze, active CMV infection was found to be associated with higher pulmonary fibrogenesis, pulmonary fibrosis score, and NT-PCP-III level (P < 0.05). The duration of ICU stay in ARDS patients with active CMV infection was significantly higher than in those without active CMV infection (P < 0.05). CONCLUSIONS: Among adult patients with ARDS, active CMV infection was related to poor clinical outcomes. Active CMV infection was associated with ARDS-associated fibroproliferation. Prophylactic and preemptive use of anti-CMV agents on pulmonary fibrosis should be assessed to determine a consensus therapeutic strategy.

Development and validation of a clinical risk model to predict the hospital mortality in ventilated patients with acute respiratory distress syndrome: a population-based study.

BACKGROUND: Large variability in mortality exists in patients of acute respiratory distress syndrome (ARDS), especially those with invasive ventilation. The aim of this study was to develop a model to predict risk of in-hospital death in ventilated ARDS patients. METHODS: Ventilated patients with ARDS from two public databases (MIMIC-III and eICU-CRD) were randomly divided as training cohort and internal validation cohort. Least absolute shrinkage and selection operator (LASSO) and then Logistic regression was used to construct a predictive model with demographic, clinical, laboratory, comorbidities and ventilation variables ascertained at first 24 h of ICU admission and invasive ventilation. Our model was externally validated using data from another database (MIMIC-IV). RESULTS: A total of 1075 adult patients from MIMIC-III and eICU were randomly divided into training cohort (70%, n = 752) and internal validation cohort (30%, n = 323). 521 patients were included from MIMIC-IV. From 176 potential predictors, 9 independent predictive factors were included in the final model. Five variables were ascertained within the first 24 h of ICU admission, including age (OR, 1.02; 95% CI: 1.01-1.03), mean of respiratory rate (OR, 1.04; 95% CI: 1.01-1.08), the maximum of INR (OR, 1.14; 95% CI: 1.03-1.31) and alveolo-arterial oxygen difference (OR, 1.002; 95% CI: 1.001-1.003) and the minimum of RDW (OR, 1.17; 95% CI: 1.09-1.27). And four variables were collected within the first 24 h of invasive ventilation: mean of temperature (OR, 0.70; 95% CI: 0.57-0.86), the maximum of lactate (OR, 1.15; 95% CI: 1.09-1.22), the minimum of blood urea nitrogen (OR, 1.02; 95% CI: 1.01-1.03) and white blood cell counts (OR, 1.03; 95% CI: 1.01-1.06). Our model achieved good discrimination (AUC: 0.77, 95% CI: 0.73-0.80) in training cohort but the performance declined in internal (AUC: 0.75, 95% CI: 0.69-0.80) and external validation cohort (0.70, 95% CI: 0.65-0.74) and showed modest calibration. CONCLUSIONS: A risk score based on routinely collected variables at the start of admission to ICU and invasive ventilation can predict mortality of ventilated ARDS patients, with a moderate performance.

Genome-wide analysis of dirigent gene family in pepper (Capsicum annuum L.) and characterization of CaDIR7 in biotic and abiotic stresses.

The dirigent (DIR and DIR-like) proteins involved in lignification, play a pivotal role against biotic and abiotic stresses in plants. However, no information is available about DIR gene family in pepper (Capsicum annuum L.). In this study, 24 putative dirigent genes (CaDIRs) were identified, their gene structure, genome location, gene duplication and phylogenetic relationship were elucidated. Tissue-specific expression analysis displayed the highest transcription levels in flower, stem and leaf. Some CaDIRs were up-regulated by virulent (CaDIR2, 3, 6, 7, 11, 14, 16, 22 and 23) and avirulent (CaDIR3, 5, 7, 16, 20, 22, 23 and 24) Phytophthora capsici strains, as well as by Methyl jasmonate, salicylic acid, NaCl and mannitol stresses. Acid-soluble lignin content increased (103.21%) after P. capsici inoculation (48-hour). Silencing of CaDIR7 weakened plant defense by reducing (~50%) root activity and made plants more susceptible (35.7%) to P. capsici and NaCl (300 mM). Leaf discs of the CaDIR7:silenced plants exposed to NaCl and mannitol (300 mM each), exhibited a significant decrease (56.25% and 48% respectively) in the chlorophyll content. These results suggested that CaDIR7 is involved in pepper defense response against pathogen and abiotic stresses and the study will provide basic insights for future research regarding CaDIRs.

Temperature Sensitivity of Soil Respiration to Nitrogen Fertilization: Varying Effects between Growing and Non-Growing Seasons.

Nitrogen (N) fertilization has a considerable effect on food production and carbon cycling in agro-ecosystems. However, the impacts of N fertilization rates on the temperature sensitivity of soil respiration (Q10) were controversial. Five N rates (N0, N45, N90, N135, and N180) were applied to a continuous winter wheat (Triticum aestivum L.) crop on the semi-arid Loess Plateau, and the in situ soil respiration was monitored during five consecutive years from 2008 to 2013. During the growing season, the mean soil respiration rates increased with increasing N fertilization rates, peaking at 1.53 µmol m-2s-1 in the N135 treatment. A similar dynamic pattern was observed during the non-growing season, yet on average with 7.3% greater soil respiration rates than the growing season. In general for all the N fertilization treatments, the mean Q10 value during the non-growing season was significantly greater than that during the growing season. As N fertilization rates increased, the Q10 values did not change significantly in the growing season but significantly decreased in the non-growing season. Overall, N fertilization markedly influenced soil respirations and Q10 values, in particular posing distinct effects on the Q10 values between the growing and non-growing seasons.

[Response of Soil Respiration to Extreme Precipitation in Semi-arid Regions].

Evaluating the response of soil microbial respiration to extreme precipitation event is significant for a better understanding about the influence of the change of precipitation regime on soil carbon cycling under global warming. A simulated experiment of extreme precipitations was conducted during the rainy season (July-September 2015) in the Changwu State Key Agro-Ecological Station, Shaanxi, China. The treatments consisted of three total precipitations in rainy season (600 mm, 300 mm, and 150 mm) and two precipitation regimes (10 mm, 150 mm; P10, P150). Soil microbial respiration varied differently in the same single rainfall event among three precipitations. The variation coefficient of soil microbial respiration under 600 mm total precipitation was 36% (P150) and 33% (P10), and 28% and 22% under 300 mm total precipitation, 43% and 29% under 150 mm total precipitation. Under 600 mm total precipitation, the cumulative soil microbial respiration under P150 was 20% less than that under P10; however, the cumulative soil respiration of P150 under 150 mm total precipitation was 22% more than that under P10; and there was no significant difference between P10 and P150 under 300 mm total precipitation. Therefore, the duration in soil water stress must be considered to estimate soil microbial respirations under extreme precipitations.

[Variation of Soil CO2 Flux and Environmental Factors Across Erosion-Deposition Sites Under Simulation Experiment].

The CO2 flux from soil is an important component of global carbon cycle, and a small variation of soil CO2 flux can prominently influence atmospheric CO2 concentration and soil organic carbon stock. Soil erosion significantly influences soil CO2 emission. However, the process of soil CO2 flux during soil erosion and soil deposition remains uncertain. At the present study, a simulated experiment on soil erosion and deposition was conducted at Changwu State Key Agro-Ecological Station, Shaanxi, China. From July to September in 2014 and 2015, soil CO2 flux was periodically measured using an automated CO2 flux system LI-8100 (LI-COR, Lincoln, NE, USA) and soil temperature and moisture were collected by series data collection system of soil temperature and soil moisture (EM50, DECAGON, USA). The measurement frequency of soil CO2 flux was once a week during 09:00 and 11:00. Soil temperature and soil moisture of 10 cm topsoil were measured continuously (at an interval of 30 minutes) during the experiment. At the same time, runoff and sediment were collected as well in each rain event, and then SOC content in sediment was measured. The results showed that soil CO2 flux between erosion and deposition sites had a significant difference (P<0.05), and soil CO2 flux at deposition site [mean value 1.38 µmol·(m2·s)-1] was 31% higher than that of soil CO2 flux at deposition site [1.05 µmol·(m2·s)-1], while temperature sensitivity at deposition site (Q10:8.14) was 3 times as high as that at erosion site (2.34). Soil moisture at deposition site was 19% higher than that at erosion site (P<0.05). Soil temperature was slightly higher at erosion site. The average SOC content (7.26 g·kg-1) increased by 6% in the sediment compared with the initial SOC content (6.83 g·kg-1). Soil moisture and SOC redistribution across erosion and deposition sites were influencing factors for soil CO2 flux under erosional environment. In conclusion, soil CO2 flux showed a significant variation at erosion site and deposition site. Changes in soil moisture and SOC contributed much to the difference in soil CO2 flux across erosion and deposition sites.

[Changes of Soil Organic Carbon and Its Influencing Factors of Apple Orchards and Black Locusts in the Small Watershed of Loess Plateau, China].

Orchard and black locust are two typical plants for comprehensive control in the small watershed of land uses in Loess area. The analysis of soil carbon sequestration function changes of growing two plants is important to gain a deep understanding of soil carbon cycle process and its influencing factors of terrestrial ecosystems under the condition of small watershed comprehensive control. The experiment was conducted in the Changwu State Key Agro-Ecological Station, Shanxi, China. SOC, TN, fine root biomass and litter amount were determined at different age apple orchards and black locusts on the slope land of Wangdonggou watershed to study the variation characteristics of soil organic carbon and its influencing factors under two measurements. The results showed that: (1) SOC and TN contents in apple orchards significantly decreased with the increased age, whereas those in black locust showed an increased tendency with the age increased. Compared with the adjacent cropland,the SOC and TN contents in year 3, year 8, year 12 and year 18 apple orchards were decreased 3. 26%, 10. 54%, 18. 08%, 22. 55% and - 8. 08%, - 0. 48%, 4. 97%, 16. 91%, respectively. However,SOC and TN contents increased 5. 31%, 32. 36%, 44. 13% and 2. 49%, 15. 75%, 24. 22%, in year 12, year 18 and year 25 black locusts, respectively. (2) The fine root biomass in year 3, year 8, year 12, and year 18 apple orchards were about 25. 97% 66. 23%, 85. 71% and 96. 10% of the adjacent cropland, respectively; and the litter amounts were all 0 g . m-2. However, compared with adjacent cropland, The fine root biomass in year 12, year 18 and year 25 black locusts were increased 23. 53%, 79. 41%, 157. 35%, respectively; and the litter input rates were 194, 298 , 433 g . (m2 . a) -1, respectively. (3) The difference of organic matter input was the major factor which drove the variability of soil carbon sequestration function of apple orchard and black locust ecosystems.

[Effects of Nitrogen Fertilization on Soil Respiration and Temperature Sensitivity in Spring Maize Field in Semi-Arid Regions on Loess Plateau].

Understanding the effects of nitrogen fertilization on soil respiration rate and its temperature sensitivity (Q10) is of critical importance to predict the variability of soil respiration in cropland. A field experiment was established in a rain-fed spring maize cropland (Zea mays L. ) in the State Key Agro-Ecological Experimental Station in the Loess Plateau in Changwu County, Shaanxi Province, China. The experiment comprised of two treatments: no N-fertilizer application ( CK) and N-fertilizer application with 160 kg N · hm(-2) (N). Soil respiration rate, soil temperature, soil moisture, yields, aboveground biomass and root biomass were measured in two continuous spring maize growing seasons from April 2013 to September 2014. The cumulative soil CO2 emissions were increased by 35% in 2013 and 54% in 2014 in N treatment as compared to CK treatment. Though nitrogen fertilization significantly increased the cumulative soil CO2 emissions (P < 0.05), it did decrease evidently the temperature sensitivity of soil respiration (P < 0.05) . The Q10 values in N treatment were decreased by 27% and 17% compared with CK treatment in 2013 and 2014, respectively. Nitrogen fertilization significantly increased the maize yields, aboveground biomass and root biomass (P < 0.05). Root biomasses in N treatment were 32% and 123% greater than those in CK treatment of 2013 and 2014, respectively. Nitrogen fertilization had no marked influence on soil temperature or moisture. Root biomass was a critical biotical factor for variation of soil respiration under nitrogen fertilization.

Phosphorus Accumulation and Sorption in Calcareous Soil under Long-Term Fertilization.

Application of phosphorus (P) fertilizers to P-deficient soils can also result in P accumulation. In this study, soil P status and P uptake by apple trees were investigated in 5-, 10-, and 15-year-old orchards in the semi-arid Loess Plateau, China, and subset soils with different soil P statuses (14-90 Olsen-P mg kg(-1)) were selected to evaluate the characteristic P adsorption. Due to the low P-use efficiency (4-6%), total soil P increased from 540 mg kg(-1) to 904 mg kg(-1), Olsen-P ranged from 3.4 mg kg(-1) to 30.7 mg kg(-1), and CaCl2-P increased from less than 0.1 mg kg(-1) to 0.66 mg kg(-1) under continuous P fertilization. The P sorption isotherms for each apple orchard were found to fit the Langmuir isotherm model (R2 = 0.91-0.98). K (binding energy) and Qm (P sorption maximum) decreased, whereas DPS (degree of phosphorus sorption) increased with increasing P concentration. CaCl2-P increased significantly with the increase of Olsen-P, especially above the change point of 46.1 mg kg(-1). Application of surplus P could result in P enrichment in P-deficient soil which has high P fixation capacity, thus posing a significant environmental risk.

[Variation characteristic in soil respiration of apple orchard and its biotic and abiotic influencing factors].

To evaluate the orchard variability of soil respiration and the response of soil respiration to its influencing factors is helpful for a deep understanding about the effects of converting cropland to apple orchard. A field experiment was conducted in the Changwu State Key Agro-Ecological Station. Soil respiration, soil temperature, soil moisture and roots biomasses were periodically measured in a mature apple orchard during 2011 and 2012. Soil respiration decreased as the distance from the trunk increased. The cumulative soil respiration in the 0.5 m-distance from the trunk was 20% and 31% higher than that in the 2 m-distance from the trunk, respectively in 2011 and 2012. The temperature sensitivity of soil respiration (Q10) was relatively lower in the 2 m-distance than that in the 0. 5 m-distance in both years. Soil temperature and soil moisture were slightly higher in the 2 m-distance, but there was no significant difference between the 2 m-distance and the 0. 5 m-distance. Soil respiration and soil temperature showed a significant exponential relationship, but there was no positive correlation between soil moisture and soil respiration. Soil temperature changes can explain seasonal variation of soil respiration well, but it could not explain its spatial variability. Root density was an important factor for the spatial variability of soil respiration and Q15. Variation of soil respiration coefficient was 23% -31%. Therefore, the distance from the trunk should be considered when estimating orchards soil respiration.