Anthropogenic, biogenic, and photochemical influences on surface formaldehyde and its significant decadal (2006-2017) decrease in the Lewiston-Clarkston valley of the northwestern United States

Formaldehyde (HCHO) is a key carcinogen and plays an important role in atmospheric chemistry. Both field measurements and Positive Matrix Factorization (PMF) modeling have been employed to investigate the concentrations and sources of HCHO in the Lewiston-Clarkston (LC) valley of the mountainous northwestern U.S. Different instruments were deployed to measure surface formaldehyde and other related compounds in July of 2016 and 2017. The measurements reveal that the average HCHO concentrations have significantly decreased to 2-5 ppb in the LC valley in comparison to its levels (10-20 ppb) observed in July 2006. This discovery with surface measurements deserves attention given that satellite retrievals showed an increasing long-term trend from 2005 to 2014 in total vertical column density of HCHO in the region, suggesting that satellite instruments may not adequately resolve small valleys in the mountainous region. Our PMF modeling identified four major sources of HCHO in the valley: (1) emissions from a local paper mill, (2) secondary formation and background, (3) biogenic sources, and (4) traffic. This study reveals that the emissions from the paper mill cause high HCHO spikes (6-19 ppb) in the early morning. It is found that biogenic volatile organic compounds (VOCs) in the area are influenced by national forests surrounding the region (e.g., Nez Perce-Clearwater, Umatilla, Wallowa-Whitman, and Idaho Panhandle National Forests). The results provide useful information for developing strategies to control HCHO levels and have implications for future HCHO studies in atmospheric chemistry, which affects secondary aerosols and ozone formation.

[Clinical analysis of 86 cases of acute fatty liver of pregnancy]

Objective: To investigate the clinical characteristics and maternal and fetal prognosis of pregnant women with acute fatty liver of pregnancy (AFLP). Methods: The clinical data of 86 AFLP pregnant women admitted to the Third Affiliated Hospital of Guangzhou Medical University from September 2017 to August 2022 were collected, and their general data, clinical characteristics, laboratory tests and maternal and fetal outcomes were retrospectively analyzed. Results: (1) General information: the age of the 86 pregnant women with AFLP was (30.8±5.4) years, and the body mass index was (21.0±2.5) kg/m2. There were 50 primiparas (58.1%, 50/86) and 36 multiparas (41.9%, 36/86). There were 64 singleton pregnancies (74.4%, 64/86) and 22 twin pregnancies (25.6%, 22/86). (2) Clinical characteristics: the main complaints of AFLP pregnant women were gastrointestinal symptoms, including epigastric pain (68.6%, 59/86), nausea (47.7%, 41/86), anorexia (46.5%, 40/86), vomiting (39.5%, 34/86). The main non-gastrointestinal symptoms were jaundice of skin and/or scleral (54.7%, 47/86), edema (38.4%, 33/86), fatigue (19.8%, 17/86), bleeding tendency (16.3%, 14/86), polydipsia or polyuria (14.0%, 12/86), skin itching (8.1%, 7/86), and 17.4% (15/86) AFLP pregnant women had no obvious symptoms. (3) Laboratory tests: the incidence of liver and kidney dysfunction and abnormal coagulation function in AFLP pregnant women was high, and the levels of blood ammonia, lactate dehydrogenase and lactic acid were increased, and the levels of hemoglobin, platelet and albumin decreased. However, only 24 cases (27.9%, 24/86) of AFLP pregnant women showed fatty liver by imageology examination. (4) Pregnancy outcomes: ① AFLP pregnant women had a high incidence of pregnancy complications, mainly including renal insufficiency (95.3%, 82/86), preterm birth (46.5%, 40/86), hypertensive disorders in pregnancy (30.2%, 26/86), gestational diabetes mellitus (36.0%, 31/86), fetal distress (24.4%, 21/86), pulmonary infection (23.3%, 20/86), disseminated intravascular coagulation (16.3%, 14/86), multiple organ dysfunction syndrome (16.3%, 14/86), hepatic encephalopathy (9.3%, 8/86), and intrauterine fetal death (2.3%, 2/86). ② Treatment and outcome of AFLP pregnant women: the intensive care unit transfer rate of AFLP pregnant women was 66.3% (57/86). 82 cases were improved and discharged after treatment, 2 cases were transferred to other hospitals for follow-up treatment, and 2 cases (2.3%, 2/86) died. ③ Neonatal outcomes: except for 2 cases of intrauterine death, a total of 106 neonates were delivered, including 39 cases (36.8%, 39/106) of neonatal asphyxia, 63 cases (59.4%, 63/106) of neonatal intensive care unit admission, and 3 cases (2.8%, 3/106) of neonatal death. Conclusions: AFLP is a severe obstetric complication, which is harmful to mother and fetus. In the process of clinical diagnosis and treatment, attention should be paid to the clinical manifestations and laboratory tests of pregnant women, early diagnosis and active treatment, so as to improve maternal and fetal outcomes.

Bradykinin/bradykinin 1 receptor promotes brain microvascular endothelial cell permeability and proinflammatory cytokine release by downregulating Wnt3a

Stroke is a life-threatening disease with limited therapeutic options. Damage to the blood-brain barrier (BBB) is the key pathological feature of ischemic stroke. This study explored the role of the bradykinin (BK)/bradykinin 1 receptor (B1R) and its mechanism of action in the BBB. Human brain microvascular endothelial cells (BMECs) were used to test for cellular responses to BK by using the Cell Counting Kit-8 assay, 5-ethynyl-2'-deoxyuridine staining, enzyme-linked immunosorbent assay, flow cytometry, immunofluorescence, cellular permeability assays, and western blotting to evaluate cell viability, cytokine production, and reactive oxygen species (ROS) levels in vitro. A BBB induced by middle cerebral artery occlusion was used to evaluate BBB injuries, and the role played by BK/B1R in ischemic/reperfusion (I/R) was explored in a rat model. Results showed that BK reduced the viability of BMECs and increased the levels of proinflammatory cytokines (interleukin 6 [IL-6], IL-18, and monocyte chemoattractant protein-1) and ROS. Additionally, cellular permeability was increased by BK treatment, and the expression of tight junction proteins (claudin-5 and occludin) was decreased. Interestingly, Wnt3a expression was inhibited by BK and exogenous Wnt3a restored the effects of BK on BMECs. In an in vivo I/R rat model, knockdown of B1R significantly decreased infarct volume and inflammation in I/R rats. Our results suggest that BK might be a key inducer of BBB injury and B1R knockdown might provide a beneficial effect by upregulating Wnt3a.

[Analysis of clinical features and risk factors for mortality in patients with culture-negative sepsis: a single-center retrospective cohort study based on MIMIC-IV]

OBJECTIVE

To compare the characteristics and outcomes of culture-positive sepsis (CPS) with culture-negative sepsis (CNS) patients in order to understand the impact of CNS on prognosis and explore the possible risk factors for mortality.

METHODS

A retrospective cohort study was conducted. Patients with sepsis were identified from the Medical Information Mart for Intensive Care database-IV v0.4 (MIMIC-IV v0.4). Patients were divided into CPS and CNS groups according to the culture results within 24 hours before and after the diagnosis of sepsis. General information, baseline characteristics, and medical operation data between CNS and CPS groups were compared. Logistic regression analysis was used to calculate the relationship between CNS and in-hospital mortality under three regression models. Chi-square analysis and mediation analysis were used to analyze the effect of initial antibiotic and prior antibiotic use within 90 days on the in-hospital mortality of CNS.

RESULTS

A total of 8 587 patients with sepsis were enrolled in the final analysis, including 5 483 patients in the CPS group and 3 104 patients in the CNS group. Compared with the CPS group, the patients in the CNS group were younger [years old: 68 (56, 79) vs. 70 (58, 81)], had higher sequential organ failure assessment (SOFA) score and higher proportion of using mechanical ventilation, renal replacement therapy and vasopressin within 24 hours after intensive care unit (ICU) admission [SOFA score: 3 (2, 5) vs. 3 (2, 4), mechanical ventilation: 48.61% (1 509/3 104) vs. 39.25% (2 152/5 483), renal replacement therapy: 13.69% (425/3 104) vs. 9.68% (531/5 483), vasopressin: 15.79% (490/3 104) vs. 13.44% (737/5 483)], longer length of ICU stay [days: 5 (3, 10) vs. 3 (2, 6)] and higher in-hospital mortality [25.00% (776/3 104) vs. 18.53% (1 016/5 483)], with significant differences (all P < 0.01). However, there was no significant difference in gender, ICU type, simplified acute physiology score II (SAPS II), and Charlson comorbidity index (CCI) score between the two groups. After adjustment for multiple confounding factors, CNS was still a risk factor for in-hospital mortality [odds ratio (OR) = 1.441, 95% confidence interval (95%CI) was 1.273-1.630, P < 0.001]. The results of Chi-square analysis and mediation analysis showed that the initial antibiotic had no significant effect on the higher in-hospital mortality of CNS, while the prior use of antibiotics within 90 days was related to higher in-hospital mortality of CNS (OR = 1.683, 95%CI was 1.328-2.134, P < 0.05). The mediating effect of CNS in prior antibiotic use within 90 days and in-hospital death was significant (Z = 5.302, P < 0.001), accounting for 7.58%.

CONCLUSIONS

Compared with CPS, CNS was more severe and had a worse prognosis. Prior use of antibiotics within 90 days may be related to the higher in-hospital mortality of CNS patients, but it could not fully explain the high mortality of CNS.

[Clinical importance of screening differential gene set of monocytes based on single-cell sequencing and digital polymerase chain reaction technology for early diagnosis of sepsis]

OBJECTIVE

To verify the specific differentiated subsets of monocytes in sepsis, and to screen and construct the differential gene set of monocytes used for early diagnosis of sepsis.

METHODS

Patients with sepsis admitted to Guangdong Provincial People's Hospital from June 2020 to March 2021 were enrolled, and peripheral blood mononuclear cells (PBMC) were extracted. Single-cell sequencing technology and pseudo-time analysis were used to verify the differential subsets of monocytes. Bioinformatics methods were used to analyze the expression of genes in differential subsets of monocytes and screen out differential genes for the preliminary construction of a candidate differential gene set. The digital polymerase chain reaction (PCR) technology was used to verify the candidate differential genes in PBMC of sepsis patients and sepsis human myeloid leukemia mononuclear cells (THP-1) models, and the Venn diagram was used to construct the final differential gene set of monocytes. Gene Expression Omnibus (GEO) database was used to validate the differential gene set of monocytes.

RESULTS

(1) The results of cell annotation and pseudo-time analysis showed that the differentiation of NEAT1⁺CD163⁺ monocyte occurred in the early stage of sepsis was significantly different from other subsets, which validated that NEAT1⁺CD163⁺ monocyte was the characteristic subset in the pathological process of sepsis. (2) Twenty-two differential genes related to sepsis were screened out from the gene expression of NEAT1⁺CD163⁺ monocyte. After further verification by digital PCR, basic leucine zipper ATF-like transcription factor (BATF), JUNB proto-oncogene, carcinoembryonic antigen-related cell adhesion molecule 4 (CEACAM4), chromosome 9 open reading frame 95 (C9orf95), G protein subunit alpha 15 (GNA15), complement C3a receptor 1 (C3AR1), transforming growth factor beta 1 (TGFB1) and mitochondrial carrier homolog 1 (MTCH1) were screened out to construct the final differential gene set of monocytes. (3) The external validation results showed that C9orf95 gene had no data in GSE154918 and GSE133822 from GEO, it was excluded during validation. In GSE154918, the expressions of BATF, JUNB, CEACAM4, GNA15, C3AR1, TGFB1, and MTCH1 in the sepsis group were significantly higher than those in the healthy control group (log₂expression level: BATF was 12.78±0.08 vs. 11.39±0.35, JUNB was 16.88±0.07 vs. 16.04±0.03, CEACAM4 was 14.73±0.08 vs. 13.77±0.05, GNA15 was 13.16±0.06 vs. 12.30±0.04, C3AR1 was 14.62±0.13 vs. 12.87±0.05, TGFB1 was 16.95±0.05 vs. 16.57±0.36, MTCH1 was 14.80±0.02 vs. 14.61±0.15, all P < 0.05). In GSE133822, the expressions of BATF, CEACAM4, GNA15, and C3AR1 in the sepsis group were significantly higher than those in the health control group (log₂expression level: BATF was 8.66±0.16 vs. 7.92±0.14, CEACAM4 was 9.20±0.16 vs. 8.36±0.20, GNA15 was 10.66±0.18 vs. 10.13±0.16, C3AR1 was 11.49±0.27 vs. 10.48±0.16, all P < 0.05), while the expressions of JUNB, TGFB1, and MTCH1 were not statistically different between two groups. The results of gene set variation analysis (GSVA) showed that the enrichment scores of monocytes differential gene set of sepsis group were significantly higher than those of the healthy control group in both GSE154918 (0.38±0.04 vs. -0.44±0.02) and GSE133822 (0.56±0.02 vs. 0.20±0.05, both P < 0.01). Receiver operator characteristic curve (ROC curve) analysis showed that the differential gene set of monocytes had a reliable diagnostic value for early sepsis with the area under ROC curve (AUC) of 0.993 [95% confidence interval (95%CI) was 0.980-1.000] in GSE154918 and 0.944 (95%CI was 0.873-1.000) in GSE133822.

CONCLUSIONS

A differential gene set of monocytes (BATF, JUNB, CEACAM4, GNA15, C3AR1, TGFB1, and MTCH1) screened out by single-cell sequencing and digital PCR technology has a reliable diagnostic value for the early sepsis, and may provide a new idea for the early diagnosis of sepsis.

[Mechanism of resveratrol on ameliorating the cognitive dysfunction induced by sepsis associated encephalopathy in rats]

OBJECTIVE

To explore the mechanism of resveratrol on ameliorating the cognitive dysfunction induced by sepsis associated encephalopathy (SAE) in rats.

METHODS

The 12 weeks old male Sprague-dawley (SD) male rats were randomly divided into sham group, sepsis group and resveratrol group, with 30 rats in each group. The rat model of sepsis was made by injecting LPS (10 mg/kg) into tail vein. The rats in sham group was given the same amount of normal saline (NS). After LPS injection, resveratrol (8 mg×kg^-1×d^-1) was intraperitoneally injected once daily for 2 days in the resveratrol group; the same amount of NS was given to the sepsis group and sham group. At 24 hours after model establishment, the cognitive function of the experimental rats was assessed by the Morris water maze test. The blood-brain barrier (BBB) permeability was evaluated by the brain water content (BWC) and Evans blue (EB) test. The protein expressions of matrix metalloproteinase 9 (MMP-9), Occludin and Claudin-5 in cortical tissue were detected by Western Blot. Double immunofluorescence was used to verify the co-localization of MMP-9 protein and the marker protein of astrocyte GFAP in the cortical tissue of rats.

RESULTS

Compared with the sham group, the escape latency in the sepsis group was significantly longer [48-hour escape latency (s): 56.56±6.43 vs. 36.62±3.32, 72-hour escape latency (s): 57.72±7.23 vs. 26.46±4.24, both P < 0.01], the BWC and extravasation of EB were increased [BWC: (84.56±2.03)% vs. (76.82±2.22)%, EB (μg/g): 17.56±2.28 vs. 6.25±1.36, both P < 0.01], the expression of MMP-9 protein was increased (MMP-9/β-actin: 0.73±0.01 vs. 0.24±0.01, P < 0.01), the protein expressions of Occludin and Claudin-5 were decreased (Occludin/β-actin: 0.45±0.02 vs. 0.86±0.04, Claudin-5/β-actin: 0.62±0.03 vs. 0.96±0.05, both P < 0.01). At the same time, the co-localization expression of MMP-9 protein and the astrocytes of the cortical were increased [MMP-9 fluorescence intensity (AU): 38.66±4.26 vs. 17.23±3.04, MMP-9 positive cells: (26.92±1.77)% vs. (12.82±1.46)%, both P < 0.01]. Compared with the sepsis group, the escape latency in resveratrol group was significantly shorter [48-hour escape latency (s): 41.42±6.27 vs. 56.56±6.43, 72-hour escape latency (s): 33.46±7.17 vs. 57.72±7.23, both P < 0.01], the BWC and extravasation of EB were decreased [BWC: (77.15±2.27)% vs. (84.56±2.03)%, EB (μg/g): 7.74±1.88 vs. 17.56±2.28, both P < 0.01], the expression of MMP-9 protein was decreased (MMP-9/β-actin: 0.25±0.01 vs. 0.73±0.01, P < 0.01), the protein expressions of Occludin and Claudin-5 were increased (Occludin/β-actin: 0.82±0.03 vs. 0.45±0.02, Claudin-5/β-actin: 0.92±0.04 vs. 0.62±0.03, both P < 0.01). At the same time, the co-localization expression of MMP-9 protein and the astrocytes of the cortical were decreased [MMP-9 fluorescence intensity (AU): 19.44±4.37 vs. 38.66±4.26, MMP-9 positive cells: (13.11±1.29)% vs. (26.92±1.77)%, both P < 0.01].

CONCLUSIONS

Resveratrol can inhibit the expression of MMP-9 protein in the astrocytes of the cortical cortex of rats, and then reduce the degradation of tight junction proteins of Occludin and Claudin-5, thereby reducing BBB permeability and eventually ameliorate the cognitive dysfunction induced by SAE.

Elevated intracranial pressure induces IL‑1β and IL‑18 overproduction via activation of the NLRP3 inflammasome in microglia of ischemic adult rats

Elevated intracranial pressure (ICP) is one of the most common complications following an ischemic stroke, and has implications for the clinical and neurological outcomes. The aim of the present study was to examine whether elevated ICP may increase IL-1β and IL-18 secretion by activating the NOD-like receptor protein 3 (NLRP3) inflammasome in microglia of ischemic adult rats. Sprague-Dawley rats that underwent middle cerebral artery occlusion were used for assessment of ICP. Reactive oxygen species (ROS) production was detected, and western blotting and immunofluorescence staining were used to determine the expression levels of Caspase-1, gasdermin D-N domains (GSDMD-N), IL-1β and IL-18 in microglial cells. ICP levels were significantly increased, which was accompanied by ROS overproduction, in the brain tissue following ischemia-reperfusion (IR) injury in rats. Treatment with 10% hypertonic saline by intravenous injection significantly reduced the ICP and ROS levels of the rats. Furthermore, high pressure (20 mmHg) combined with oxygen-glucose deprivation (OGD) treatment resulted in increased ROS production in BV-2 microglial cells compared with those subjected to OGD treatment alone in vitro. Elevated pressure upregulated the expression of Caspase-1, GSDMD-N, IL-18 and IL-1β in IR-treated or OGD-treated microglia both in vivo and in vitro. More importantly, Caspase-1, GSDMD-N, IL-18 and IL-1β expression in microglia was significantly downregulated when elevated pressure was reduced or removed. These results suggested that elevated ICP-induced IL-1β and IL-18 overproduction via activation of the NLRP3 inflammasome by ischemia-activated microglia may augment neuroinflammation.

Increased percentage of PD-L1+ natural killer cells predicts poor prognosis in sepsis patients: a prospective observational cohort study

Background

Natural killer (NK) cells play a major role in immune tolerance after sepsis, and the programmed cell death 1 (PD-1) and programmed cell death ligand 1 (PD-L1) system mediates evasion of host immunity. The correlation between PD-L1 levels in NK cells and the prognosis of patients with sepsis, however, has not been elucidated. Thus, it was hypothesized that PD-L1 in NK cells could be a novel biomarker of the mortality for sepsis patients.

Methods

A prospective, observational, cohort study in a general intensive care unit had earlier enrolled patients according to the sepsis-3 criteria, and peripheral blood samples were collected within 24 h post-recruitment. The expression of four co-signaling molecules (PD-1, CD28, PD-L1, and CD86) in NK cells was assayed, and the sequential organ failure assessment (SOFA) scores were recorded on day 1. Patients were followed up until 28 days. Multivariate regression analysis assessed the independent risk factors for 28-day mortality. The association between biomarkers and 28-day mortality was assessed by Cox regression survival analysis. The accuracy of biomarkers for mortality was determined by the area under the receiver operating characteristic (ROC) curve (AUC) analysis.

Results

A total of 269 patients were recruited, and 114 patients were finally included for final analysis. Of these, 30 (26.3%) patients died during 28 days. The percentage of PD-L1⁺ NK cells (OR 1.022; 95% CI 1.002–1.043) and SOFA scores (OR 1.247; 95% CI 1.092–1.424) were independent risk factors for 28-day mortality. The AUC of the percentage of PD-L1⁺ NK cells, SOFA scores, and their combination model were 0.655 (0.559–0.742), 0.727 (0.635–0.807) and 0.808 (0.723–0.876), respectively. The combination model was the indicator with the best AUC to predict mortality in 28 days (all p < 0.05). Patients with the percentage of PD-L1⁺ NK cells above the cutoff point 5.58% (hazard ratio (HR) 10.128 (1.372–74.772), p = 0.001), and the combination model prediction possibility above 0.1241 (HR 13.730 (3.241–58.158), p < 0.001) were the indexes that had greater discriminative capacity to predict 28 days mortality.

Conclusions

The percentage of PD-L1⁺ NK cells at admission serves as a novel prognostic biomarker for predicting mortality and contributes to improve the predictive capacity of SOFA score in patients with sepsis.

[Effect of hypercapnia on the clinical prognosis and severity of infection in patients with severe community-acquired pneumonia]

OBJECTIVE

To investigate the effect of hypercapnia at admission on the clinical prognosis and the severity of infection in patients with severe community-acquired pneumonia (SCAP).

METHODS

The clinical data of 219 SCAP patients admitted to the department of emergency and critical care medicine of Guangdong Provincial People's Hospital from December 2017 to November 2019 were retrospectively analyzed. Based on the partial pressure of arterial carbon dioxide (PaCO₂) within 1 day after admission, the patients were divided into hypocapnia group [HO group, PaCO₂ < 35 mmHg (1 mmHg = 0.133 kPa)], normal carbonation group (NC group, PaCO₂ 35-45 mmHg) and hypercapnia group (HC group, PaCO₂ > 45 mmHg). The clinical parameters of patients, such as gender, age, underlying diseases, white blood cell (WBC), procalcitonin (PCT), C-reactive protein (CRP), interleukin-6 (IL-6), pH value and lactate (Lac) within 1 day after admission were reviewed. The oxygenation index (PaO₂/FiO₂), pneumonia severity index (PSI) score and acute physiology and chronic health evaluation II (APACHE II) score were evaluated. The change tendencies of each index on day 1, day 3, and day 5 after admission were observed subsequently. Meanwhile, the rate of invasive mechanical ventilation (IMV), length of hospital stays and 28-day mortality among three groups were compared. Kaplan-Meier survival analysis was performed to assess the 28-day cumulative survival rate of patients with SCAP among three groups. Multivariate Logistic regression analysis was used to screen the risk factors of IMV and 28-day death in patients with SCAP.

RESULTS

Compared with the HO group (n = 68) and NC group (n = 72), the HC group (n = 79) had higher proportion of preexisting comorbid chronic obstructive pulmonary disease (COPD) and PSI score, lower PCT, CRP, IL-6, and pH values. Compared with the HO group and NC group, there were smaller improvement trends on the levels of WBC, PCT, CRP, IL-6, PaO₂/FiO₂ and Lac at day 3 and day 5 as compared with day 1 in the HC group. On the 5th day after admission, the levels of WBC, PCT, CRP, IL-6, and Lac in the HC group were significantly higher than those in the HO group and NC group [WBC (×10⁹/L): 18.33±1.44 vs. 10.89±2.37, 11.15±1.74; PCT (μg/L): 5.04±1.18 vs. 3.46±0.87, 3.58±0.83; CRP (mg/L): 78.43±7.17 vs. 54.24±4.97, 57.93±5.39; IL-6 (ng/L): 75.35±11.92 vs. 60.11±10.27, 57.88±12.34; Lac (mmol/L): 4.36±1.24 vs. 0.78±0.39, 0.86±0.64; all P < 0.01], and the lowest in PaO₂/FiO₂ was found in the HC group as compared with the HO and NC groups (mmHg: 171.31±6.73 vs. 226.68±7.36, 225.93±6.92, both P < 0.01). Compared with the HO group and NC group, the HC group had highest proportion of IMV (29.1% vs. 22.1%, 22.2%, both P < 0.01) and 28-day mortality (26.6% vs. 13.2%, 13.9%, both P < 0.01). Even when the patients with COPD were excluded from the analysis, the differences persisted among the groups. Kaplan-Meier survival analysis suggested that HC group had a higher 28-day cumulative survival rate as compared with the HO and NC groups (Log-Rank test: χ₁² = 4.976, P₁ = 0.026; χ₂² = 4.629, P₂ = 0.031). Multivariate Logistic regression analysis showed that IL-6, PSI score and hypercapnia within 1 day and PCT on the 5th day after admission were the independent risk factors of requiring IMV and 28-day death in patients with SCAP [odds ratio (OR) were 0.325, 1.229, 1.396, 1.313, respectively, all P < 0.01]. Even when patients with COPD were excluded from the analysis, the above results had not been changed.

CONCLUSIONS

Hypercapnia at admission was associated with higher proportion of IMV and 28-day mortality in patients with SCAP, which may be related to its early suppression of inflammation and then increment of infection.

Hypercapnia exacerbates the disruption of the blood‑brain barrier by inducing interleukin‑1β overproduction in the blood of hypoxemic adult rats

Refractory hypoxemia is the main symptom of acute respiratory distress syndrome (ARDS). Low tidal volume ventilation is routinely applied in clinical practice to correct hypoxemia, which aims to prevent ventilator‑induced lung injury. However, this ventilation strategy inevitably leads to hypercapnia. Our previous study demonstrated that hypercapnia aggravated cognitive impairment in hypoxemic rats; however, the underlying mechanism remains unclear. The aim of the present study was to investigate whether hypercapnia exacerbates the blood‑brain barrier (BBB) disruption through inducing interleukin (IL)‑1β overproduction in the blood of hypoxemic rats. The BBB permeability in a rat model of hypercapnia/hypoxemia was evaluated. The levels of IL‑1β in the blood of rats and human whole‑blood cultures were assessed. The expression of IL‑1 receptor 1 (IL‑1R1), phosphorylated IL‑1R1‑associated kinase (p‑IRAK‑1) and tight junctional proteins in cerebral vascular endothelial cells was examined in vitro and in vivo. In addition, IL‑1Ra, an IL‑1 receptor antagonist, was used to determine whether hypercapnia affects tight junctional protein expression in hypoxic cerebral vascular endothelial cells through inducing IL‑1β overproduction. It was observed that hypercapnia alone did not disrupt the BBB, but aggravated the damage to the BBB integrity in hypoxemic rats. Hypercapnia increased IL‑1β expression in the blood of hypoxemic rats as well as in hypoxic human whole‑blood cultures. IL‑1R1 and p‑IRAK‑1 expression was increased, while that of tight junctional proteins was reduced by hypercapnia in hypoxemic cerebral vascular endothelial cells in vitro and in vivo. Additionally, the expression of tight junctional proteins was markedly increased following treatment with IL‑1Ra. These results suggest that hypercapnia‑induced IL‑1β overproduction in the hypoxemic blood may decrease tight junctional protein expression in cerebrovascular endothelial cells via the IL‑1R1/p‑IRAK‑1 pathway, further disrupting BBB integrity, and eventually resulting in increased BBB permeability.

Hypercapnia Exacerbates the Blood-Brain Barrier Disruption Via Promoting HIF-1a Nuclear Translocation in the Astrocytes of the Hippocampus: Implication in Further Cognitive Impairment in Hypoxemic Adult Rats

Hypercapnia in combination with hypoxemia is usually present in severe respiratory disease in the intensive care unit (ICU) and can lead to more severe cognitive dysfunction. Increasing evidence has indicated that the compromised blood–brain barrier (BBB) in the hippocampus in hypoxemia conditions can result in cognitive dysfunction. However, the role and underlying mechanism of hypercapnia in the BBB disruption remains poorly known. A rat model of hypercapnia was first established in this study by intubation and mechanical ventilation with a small-animal ventilator. After this, the cognitive function of the experimental rats was assessed by the Morris water maze test. The BBB permeability was evaluated by the Evans Blue (EB) test and brain water content (BWC). Western blot analysis was carried out to detect the protein expressions of total and nuclear hypoxia-inducible factor-1α (HIF-1α), matrixmetalloproteinase-9 (MMP-9) and Aquaporins-4 (AQP-4) in the hippocampus tissue. Double immunofluorescence further verified the protein expression of different biomarkers was localized in the astrocytes of the hippocampus. Hypercapnia alone did not disrupt the BBB, but it could further enhance the BBB permeability in hypoxemia. Concomitantly, up-regulation of nuclear HIF-1α, AQP-4, MMP-9 protein expression along with increased degradation of the occludin and claudin-5 proteins was found in the hypercapnia rat model, while the total HIF-1α remained unchanged. Interestingly, these changes were independent of the acidosis induced by hypercapnia. Of note, after premedication of 2-Methoxyestradiol (2ME2, an inhibitor of HIF-1α nuclear translocation), the disrupted BBB could be restored resulting in improvement of the cognitive impairment. Meanwhile, accumulation of nuclear HIF-1α, protein expression of AQP-4 and MMP-9 and protein degradation of the occludin and claudin-5 were decreased. Thus, our study demonstrated that hypercapnia can further disrupt the BBB through promoting HIF-1α nuclear translocation and up-regulation of AQP-4 and MMP-9 in hypoxemia. It is therefore suggested that the cascade of hypercapnia-induced nuclear HIF-1α protein translocation in hypoxia-activated astrocytes may be a potential target for ameliorating cognitive impairment.

Single-cell transcriptomics reveals the alteration of peripheral blood mononuclear cells driven by sepsis

Background

Sepsis is a serious systemic inflammatory response syndrome caused by infection, with an extremely high mortality rate. Peripheral blood mononuclear cells (PBMCs) played a key role in the immune response against infection, whose components and functions were altered radically in Sepsis. Here, we wondered to characterize the alteration of PBMCs in sepsis at the single-cell transcriptional level.

Methods

We isolated PBMCs from seven septic patients and four donors. Based on BD Rhapsody, PBMCs were generated by single-cell RNA sequencing, and cell types were clustered and named by unsupervised clustering and annotation analysis.

Results

PBMCs were profiled for 6 kinds of cell types, the biological properties of T cell and monocytes were shown in a detailed manner. We noticed that monocytes could be clustered into 6 subsets, with great heterogeneity in the alteration of composition, gene profile, and signaling pathways driven by sepsis. Moreover, the expression of representative genes was high associated with septic clinical indicators in clusters of monocytes, such as NEAT1.

Conclusions

Although the study was preliminary, we revealed sepsis-specific alteration of PBMCs and associated pathways. These results give a panoramic picture of PBMCs in composition, genes profiles, and pathway signatures that are driven by sepsis, which offers a unique perspective to understand disease progression or treatment in clinical practice.

Peri-operative risk factors for in-hospital mortality in acute type A aortic dissection

Background

Acute type A aortic dissection (TAAD) is cardiovascular emergency and requires surgical interventions. In-hospital mortality rate of surgical-treated TAAD patients remains high. We aim to examine the prognostic implications of peri-operative parameters to identify high-risk patient for in-hospital mortality.

Methods

A total of 264 surgically treated TAAD patients were included in this study. The association between in-hospital mortality and peri-operative parameters were examined.

Results

Thirty patients (11.36%) died during hospitalization. Patients with higher Apache II score had a significantly higher rate of in-hospital mortality when compared with patients scored ≤20 in unadjusted model [Score 21-25: HR =12.9 (1.7-100.8), P=0.0148; Score >25: HR =94.5 (12.6-707.6), P<0.0001]. Patients with Sbp >120 mmHg, Cr >200 mmol/L (both at admission and after surgery), BUN >8.2 mmol/L (both at admission and after surgery), AST >80 µ/L, aortic cross-clamping time >120 min and cardiopulmonary bypass time (CPBT) >230 min were also significantly related to higher rate of in-hospital mortality in univariate analysis. In multivariable analysis, APACHE II score [Score 21-25: HR =9.5 (1.2-74.4), P=0.032; Score >25: HR =51.0 (6.7-387.7), P=0.0001], AST >80 µmol/L [HR =2.3 (1.1-4.8), P=0.0251], aortic cross-clamping time >120 min (HR =2.9 (1.1-7.7), P=0.0315) remained significant in predicting TAAD in-hospital mortality.

Conclusions

APACHE II score could be a useful tool to predict TAAD in-hospital mortality. AST >80 µ/L and aortic cross-clamping time >120 min were also independent predictors.

[β1 receptor blocker decreases the myocardial inflammation in the sepsis adult rats through inhibition of TLR4/NF-ΚB signaling pathway]

OBJECTIVE

To explore whether β1 receptor blocker could decrease the myocardial inflammation through the Toll-like receptor 4/nuclear factor-ΚB (TLR4/NF-ΚB) signaling pathway in the sepsis adult rats.

METHODS

Sixty male Wistar rats (250-300 g) aged 3 months old were allocated to four groups by random number table (n = 15): sham operation group (S group), sepsis model group (CLP group), β1 receptor blocker esmolol intervention group (ES group), and inhibitor of the TLR4 E5564 intervention group (E5564 group). The rat sepsis model was established by cecal ligation and puncture (CLP); S group of rats underwent only an incision. Rats in S group, CLP group and E5564 group were subcutaneous injected with 0.9% sodium chloride (NaCl) 2.0 mL/kg. Besides, the rats in ES group were injected with esmolol (15 mg×kg^-1×h^-1) by micro pump through the caudal vein. The rats in E5564 group were injected with E5564 (0.3 mg×kg^-1×h^-1) by micro pump through the caudal vein 1 hour before the CLP surgery. Samples were collected 6 hours after the modelling in each group. The average arterial pressure (MAP) and cardiac output index (CI) were monitored by PU electrical conduction ECG monitor. The levels of serum cardiac troponin I (cTnI), interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) were detected by enzyme linked immunosorbent assay (ELISA). The expressions of TLR4, NF-ΚB p65, IL-1β, TNF-α in myocardial tissue was detected by Western Blot.

RESULTS

There was no significant difference in MAP in each group. Compared with the S group, the CI in the CLP group was significantly decreased, the levels of serum cTnI, IL-1β, TNF-α were significantly increased, the protein expressions of myocardial tissue TLR4, NF-ΚB p65, IL-1β and TNF-α were significantly increased. Compared with the CLP group, the CI in the ES group and E5564 group were significantly increased (mL×s^-1×m^-2: 58.6±4.3, 58.9±4.4 vs. 41.2±3.9, both P < 0.01), the levels of serum cTnI, IL-1β and TNF-α were significantly decreased [cTnI (μg/L): 1 113.81±26.64, 1 115.74±25.90 vs. 1 975.96±42.74; IL-1β (ng/L): 39.6±4.3, 38.9±4.4 vs. 61.2±3.9; TNF-α (ng/L): 43.1±2.8, 48.7±2.6 vs. 81.3±4.4, all P < 0.01], the protein expressions of myocardial tissue NF-ΚB p65, IL-1β, TNF-α were significantly decreased (NF-ΚB p65/β-actin: 0.31±0.03, 0.43±0.04 vs. 0.85±0.08; IL-1β/β-actin: 0.28±0.05, 0.32±0.03 vs. 0.71±0.06; TNF-α/β-actin: 0.18±0.04, 0.28±0.03 vs. 0.78±0.07, all P < 0.01), but there was no significant difference in protein expression of TLR4 (TLR4/β-actin: 0.89±0.07, 0.87±0.09 vs. 0.95±0.09, both P > 0.05). There was no significant difference in CI, the levels of serum cTnI, IL-1β, TNF-α, and the protein expressions of myocardial tissue TLR4, NF-ΚB p65, IL-1β, TNF-α between ES group and E5564 group (all P > 0.05).

CONCLUSIONS

β1 receptor blocker esmolol may inhibit myocardial inflammatory response in sepsis adult rats through TLR4/NF-ΚB signaling pathway, thereby alleviating sepsis-induced myocardial injury.

Hypertonic saline downregulates endothelial cell-derived VEGF expression and reduces blood-brain barrier permeability induced by cerebral ischaemia via the VEGFR2/eNOS pathway

The aim of the present study was to explore the possible mechanisms by which hypertonic saline (HS) effectively ameliorates cerebral oedema via the vascular endothelial growth factor receptor 2 (VEGFR2)-mediated endothelial nitric oxide synthase (eNOS) pathway of endothelial cells in rats. A middle cerebral artery occlusion (MCAO) model in Sprague-Dawley rats and an oxygen-glucose deprivation (OGD) model in cells were used in the present study. Evans blue (EB) staining and a horseradish peroxidase flux assay were performed to evaluate the protective effect of 10% HS on the blood-brain barrier (BBB). The expression levels of vascular endothelial growth factor (VEGF), VEGFR2, zonula occludens 1 (ZO1) and occludin were quantified. The results demonstrated that 10% HS effectively reduced EB extravasation in the peri-ischaemic brain tissue. At 24 h after MCAO, the protein expression levels of VEGF and VEGFR2 in the peri-ischaemic brain tissue were downregulated following treatment with 10% HS. In vitro experiments demonstrated that the permeability of a monolayer endothelial cell barrier was decreased significantly following HS treatment. In addition, VEGF and VEGFR2 protein expression levels were increased in endothelial cells under hypoxic conditions, but that effect was suppressed by HS treatment. Furthermore, HS inhibited the downregulation of ZO1 and occludin effectively, possibly through the VEGFR2/phospholipase C γ1 (PLCγ1)/eNOS signalling pathway. In conclusion, 10% HS may alleviate cerebral oedema through reducing ischaemia-induced BBB permeability, as a consequence of inhibiting VEGFR2/PLCγ1/eNOS-mediated downregulation of ZO1 and occludin.

Correction to: Topical antimicrobial prophylaxis in colorectal surgery for the prevention of surgical wound infection: a systematic review and meta-analysis

Unfortunately, an author name (Nuzhat Iqbal) was missed out in the original publication. The complete updated author list is given below.

[Relationship between sepsis-induced immunosuppression and multi-drugs resistant bacteria]

OBJECTIVE

Sepsis is a life-threatening organ dysfunction caused by dysregulated host response to infection. Immunosuppression is an important factor of secondary infection in the late state of sepsis, including multi-drugs resistant bacteria, which ultimately leads to the death of patients. The aim of this article was to help clinical staffs better manage patients with sepsis, improve long-term survival rate of the patients, and reduce their re-hospitalization rate by reviewing the relationship between sepsis-induced immunosuppression and multi-drugs resistant bacteria through three aspects: the mechanism of sepsis-induced immunosuppression, the mechanism of antibiotic resistance and the relationship between sepsis-induced immunosuppression and secondary infections.

Long non‑coding RNA DILC is involved in sepsis by modulating the signaling pathway of the interleukin‑6/signal transducer and activator of transcription 3/Toll‑like receptor 4 axis

Sepsis is characterized by systemic inflammatory responses. In the present study, the role of deleted in liver cancer 1 (DILC), interleukin (IL)‑6, signal transducer and activator of transcription 3 (STAT3), and Toll‑like receptor 4 (TLR4) in the pathogenesis of sepsis was investigated. Reverse transcription‑quantitative polymerase chain reaction analysis and western blotting were performed to evaluate the effects of lipopolysaccharide (LPS) on the expression of DILC, IL‑6, STAT3, and TLR4, in addition to the effects of DILC and IL‑6 on the synthesis of tumor necrosis factor (TNF‑α), chemokine ligand 5 (CCL5), E‑selectin and C‑X‑C motif chemokine receptor 1 (CXCR1). In addition, the regulatory association between DILC, IL‑6, STAT3 and TLR4 was investigated. LPS reduced the expression level of DILC, and enhanced the expression of IL‑6, STAT3 and TLR4. DILC directly and negatively regulated the synthesis of IL‑6, as demonstrated by the markedly decreased luciferase activity in cells transfected with a wild‑type DILC plasmid. On the other hand, compared with the scramble control, DILC and IL‑6 small interfering (si)RNAs significantly suppressed the expression of IL‑6, STAT3 and TLR4. In addition, DILC siRNA enhanced the expression of IL‑6, STAT3 and TLR4, whereas the expression levels of TNF‑α, CCL5, E‑selectin and CXCR1 in LPS‑treated THP‑1 cells were downregulated following transfection with DILC and IL‑6 siRNAs. In patients with sepsis, DILC expression was inhibited, although the expression levels of IL‑6, STAT3 and TLR4 were upregulated. In addition, the expression levels of TNF‑α, CCL5, E‑selectin and CXCR1 in patients with sepsis were higher compared with normal subjects. Therefore, DILC may mediate the crosstalk between the cascades of IL‑6/STAT3 and TNF‑α signaling, indicating that DILC may act as a prognostic biomarker of sepsis, and may serve as a potential therapeutic target for the treatment of sepsis.

Topical antimicrobial prophylaxis in colorectal surgery for the prevention of surgical wound infection: a systematic review and meta-analysis

BACKGROUND

Among the techniques investigated to reduce the risk of surgical wound infection or surgical space infection (SSI) in patients having colorectal surgery are topical application of antimicrobials (antibiotics and antiseptics) to the open wound or immediately after closure. The aim of the present study was to perform a systematic review of the literature on those treatments, with the exception of antibiotic ointments applied to closed skin, which are adequately assessed elsewhere, and a meta-analysis.

METHODS

Only randomized trials of patients having only colorectal surgery were included in this review. Studies were sought in MEDLINE, EMBASE, the Cochrane Register of Controlled Trials, Clinical Trials.gov, and the World Health Organization Internet clinical trials register portal. In addition, reference lists of included studies and other published reviews were screened. Meta-analysis was performed for all included studies and subgroup analyses done for each individual intervention. Risk of bias was assessed for each included study, paying particular attention to the preoperative antibiotic prophylaxis used in each study. Sensitivity analyses were done to investigate heterogeneity of the analyses, excluding those studies with a significant risk of bias issues. Absolute risk reduction (RR) was calculated. The overall quality of the evidence for each individual intervention was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, and was classified as high, moderate, low or very low.

RESULTS

A total of 30 studies are included in this review with 5511 patients, 665 of whom had SSI. The interventions included: 10 studies of gentamicin impregnated sponge or beads wound inlays, 4 studies of chlorhexidine impregnated suture, 11 studies of direct wound lavage or powder application or injection of antibiotics before closure, 4 studies of ionized silver dressing applied to the closed skin, and 1 study of vitamin E oil applied to the open wound. All but one study used preoperative antibiotic prophylaxis in addition to topical procedures, although, in some studies, the systemic antibiotic prophylaxis was not the same between groups or varied significantly from the recommended guidelines. Use of gentamycin sponge did not decrease SSI (RR 0.93, 95% CI 0.75-1.16; low-quality evidence) even after including only the studies of abdominal wounds (RR 1.02, 95% CI 0.80-1.30; low-quality evidence). However, sensitivity analysis excluding studies at high risk of bias decreased the heterogeneity and increased the effect of the prophylaxis for all wounds (RR 0.5, 95% CI 0.33-0.78; low-quality evidence) and for abdominal wounds only (RR 0.38, 95% CI 0.20-0.72; moderate-quality evidence). Chlorhexidine impregnated suture showed no effect on SSI (RR 0.79, 95% CI 0.56-1.10; low-quality evidence) and an increased efficacy after sensitivity analysis (RR 0.42, 95% CI 0.22-0.79; low-quality evidence). Antibiotic lavage showed a significant decrease in SSI (RR 0.45, 95% CI 0.26-0.79; low-quality evidence) which increased after sensitivity analysis (RR 0.33, 95% CI 0.15-0.72; moderate-quality evidence). Application of silver dressing to the closed wound resulted in a decrease of SSI (RR 0.55, 95% CI 0.35-0.85; moderate-quality evidence). The one study of topical vitamin E oil applied to the open wound showed a significant risk reduction (RR 0.22, 95% CI 0.05-0.98; low-quality evidence).

CONCLUSIONS

Each of these interventions appears to be effective in decreasing SSI, but the number of studies for each is small and the quality of evidence is very low to moderate. Within the various outcomes of GRADE assessment, even a moderate classification suggests that further studies may well have very different results.. No randomized trials exist of combinations of two or more of the above interventions to see if there is a combined effect. Future studies should make sure that the antibiotic used preoperatively is uniform within a study and is consistent with the current guidelines. Deviation from this leads to a significant heterogeneity and risk of bias.

Nutrition and physical activity related school environment/policy factors and child obesity in China: a nationally representative study of 8573 students in 110 middle schools

BACKGROUND

Obesity is a serious threat to global health. School is a key setting for obesity intervention. Research on school risk factors for child obesity is limited in developing countries.

OBJECTIVES

To examine regional variations in obesity and school environments/policies and their associations among students in China.

METHODS

Analyses were based on the first nationally representative sample of 8573 9^th graders in 110 middle schools from 28 regions across China. Multilevel models tested associations between school factors and child self-reported weight outcomes and by school urbanicity setting (urban, rural).

RESULTS

Overweight/obesity rate is higher among boys and in urban areas. Schools in rural areas, or less developed regions, promote longer on-campus life, as is indicated by the presence of school cafeterias, night study sessions and longer class hours. Multilevel models show that (i) school cafeterias (OR = 2.53, 95% CI = 1.35-4.75) and internet bars close to school (OR = 1.63, 95% CI = 1.15-2.30) are associated with increased overweight/obesity risk in rural areas, especially for boys; (ii) school night study sessions are associated with lower overweight/obesity risk (OR = 0.69, 95% CI = 0.50-0.96) in rural areas.

CONCLUSIONS

China has large regional disparities in school environment/policies related to nutrition and physical activity. Some school factors are associated with students' weight status, which vary across gender and areas. Future school-based interventions should attend to diverse regional contexts.

Magnetic resonance spectroscopy for assessment of brain injury in the rat model of sepsis

The diagnostic value of magnetic resonance spectroscopy (MRS), T2-weighted imaging (T2WI) and serum markers of brain injury in a rat model of sepsis were investigated. Rats were randomly divided into the control group and 6, 12 and 24 h after lipopolysaccharide-injection groups. Brain morphology and metabolism were assessed with T2WI magnetic resonance imaging (MRI) and MRS. Serum and brain tissue samples were then collected to examine the concentrations of neuron-specific enolase (NSE) and S100-β protein. Brain T2WI showed no differences between the groups. N-acetylaspartate/choline (NAA/Cr) ratio measured by MRS showed different degrees of decrease in the sepsis groups, and serum NSE and S100-β concentrations were increased compared with the control group. Apoptosis rates were measured in the right hippocampal area, and there were statistically significant differences between the indicated groups and the control group (p<0.05). The correlation between apoptosis rate and NAA/Cr ratio was closer than that between apoptosis rate and NSE or S100-β (−0.925 vs. 0.434 vs. 0.517, respectively). In conclusion, MRS is a sensitive, non-invasive method to investigate complications of brain injury in septic rats, which may be utilized for the early diagnosis of brain injury caused by sepsis.

Neutralization of Interleukin-17 Attenuates Cholestatic Liver Fibrosis in Mice

Anti-inflammation strategy is one of the proposed therapeutic approaches to hepatic fibrosis. IL-17 is critical in inflammation, but the role of IL-17 in liver fibrosis has not yet been elucidated. In this study, we investigate the role of IL-17 on bile duct ligation-induced liver injury and fibrosis in C57BL/6 mice. Animals were sacrificed at designated times, and serum and liver tissues were collected for analysis of liver function and serum IL-6, IL-1β, tumour necrosis factor-alpha (TNF-α) and transforming growth factor-β (TGF-β) levels. IL-17 blockade with anti-IL-17A mAb significantly improved liver function and decreased hepatocellular necrosis, pro-inflammatory cytokines, neutrophils and macrophages influx. Furthermore, CD3 + and CD8 + lymphocytes, neutrophils and macrophages were found to express IL-17, and neutrophils are the principal IL-17-producing cells after BDL-induced liver injury. These data indicated that IL-17 signal contributes to the pathogenesis of cholestatic liver injury and blocked of IL-17 could potentially benefit patients with cholestatic liver disease.

Minifish shows high genetic variation in mtDNA size

The genus Paedocypris is a newly described taxon of minifish species that are characterized by extensive chromosome evolution and one of the smallest known vertebrate nuclear genomes. Paedocypris features a tiny adult size, a short generation time, low fecundity and fragmented tropical habitats, which are factors that favor rapid speciation. Most recently, we have revealed that P. progenetica (Pp), the type species of the genus Paedocypris, has an unusual mtDNA bearing - within its D-loop - a tandem array of a 34-bp repeat sequence called the minifish repeat, which shows compromised replication efficiency in vitro. Here we report that Pp exhibits high genetic variation in mtDNA size. The efficiency of D-loop amplification was found to depend upon primers. Interestingly, Pp individuals of one and the same population differed drastically in mtDNA size resulting from varying copy numbers of the minifish repeat. We conclude that minifish has a high mutation rate and perhaps represents a rapidly evolving taxon of vertebrates.

Interleukin 8 enhances the immune response of ducks to avian influenza vaccine

Interleukins are reported to be valuable immunostimulants in enhancing the immune efficiency of conventional vaccines. In this study, the effect of expression of interleukin 8 (IL-8) on the immune response of ducks to avian influenza vaccine was investigated. The results showed that the serum antibody titer, lymphocyte transformation efficiency and serum interferon gamma (IFN-γ) level of ducks injected with avian influenza vaccine along with a plasmid expressing duck IL-8 were higher than those of ducks injected with conventional immunostimulant Astragalus polysaccharide (APS) or empty plasmid. Therefore, the duck IL-8 may be used as a good immunostimulant to enhance the immune efficiency of avian influenza vaccine in ducks.

Minifish mtDNA has abundance of repeat sequences and inefficient replication in vitro

Paedocypris is a newly described minifish genus endemic to Southeast Asia. Besides a tiny adult size of ~8 mm in length, minifish feature fragmentary habitats of acidic peat blackwater swamps, an unusual reproduction mode, truncated development and one of the smallest known genomes. A complete sequence is absent for the minifish mitochondrial DNA (mtDNA). Here we report the complete mtDNA sequence and its unusual feature in the minifish P. progenetica (Pp). We show that the Pp mtDNA is a circular molecule of 17,382 bp in length and has the same number of similarly oriented genes as in other vertebrates. Specifically, it comprises 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes and 1 D-loop. Surprisingly, the D-loop is elusive for amplification by standard PCR conditions. The D-loop possesses a 28-bp dinucleotide TA repeat and more intriguingly, up to 25 copies of a 34-bp tandem repeat sequence. These tandem repeats predict the formation of paired regions. Hence, besides a generally conserved mtDNA with other vertebrates, the Pp mtDNA features an unusual D-loop and compromised DNA replication in vitro.

Severe influenza A(H1N1)pdm09 infection induces thymic atrophy through activating innate CD8(+)CD44(hi) T cells by upregulating IFN-γ

Thymic atrophy has been described as a consequence of infection by several pathogens including highly pathogenic avian influenza virus and is induced through diverse mechanisms. However, whether influenza A(H1N1)pdm09 infection induces thymic atrophy and the mechanisms underlying this process have not been completely elucidated. Our results show that severe infection of influenza A(H1N1)pdm09 led to progressive thymic atrophy and CD4⁺CD8⁺ double-positive (DP) T-cells depletion due to apoptosis. The viruses were present in thymus, where they activated thymic innate CD8⁺CD44^hi single-positive (SP) thymocytes to secrete a large amount of IFN-γ. Milder thymic atrophy was observed in innate CD8⁺ T-cell-deficient mice (C57BL/6J). Neutralization of IFN-γ could significantly rescue the atrophy, but peramivir treatment did not significantly alleviate thymic atrophy. In this study, we demonstrated that thymic innate CD8⁺CD44^hi SP T-cells have critical roles in influenza A(H1N1)pdm09 infection-induced thymic atrophy through secreting IFN-γ. This exceptional mechanism might serve as a target for the prevention and treatment of thymic atrophy induced by influenza A(H1N1)pdm09.

Mechanism for adhesion G protein-coupled receptor GPR56-mediated RhoA activation induced by collagen III stimulation

GPR56 is a member of the adhesion G protein-coupled receptor (GPCR) family. Despite the importance of GPR56 in brain development, where mutations cause a devastating human brain malformation called bilateral frontoparietal polymicrogyria (BFPP), the signaling mechanism(s) remain largely unknown. Like many other adhesion GPCRs, GPR56 is cleaved via a GPCR autoproteolysis-inducing (GAIN) domain into N- and C-terminal fragments (GPR56N and GPR56C); however, the biological significance of this cleavage is elusive. Taking advantage of the recent identification of a GPR56 ligand and the presence of BFPP-associated mutations, we investigated the molecular mechanism of GPR56 signaling. We demonstrate that ligand binding releases GPR56N from the membrane-bound GPR56C and triggers the association of GPR56C with lipid rafts and RhoA activation. Furthermore, one of the BFPP-associated mutations, L640R, does not affect collagen III-induced lipid raft association of GPR56. Instead, it specifically abolishes collagen III-mediated RhoA activation. Together, these findings reveal a novel signaling mechanism that may apply to other members of the adhesion GPCR family.

Correlation between hardness and bond orientation of vanadium borides

The relationship between hardness and bond characteristic of vanadium borides was investigated by first-principles approach.

Correlation between hardness and pressure of CrB4

The correlation between hardness and pressure for two different structures of CrB₄ is investigated by a first-principles approach.

Improving the in vivo persistence, distribution and function of cytotoxic T lymphocytes by inhibiting the tumor immunosuppressive microenvironment

Adoptive cell transfer immunotherapy of malignant tumors has the problem of symbiosis between effector cells and tumor cells, a short in vivo residence time, and a poor killing efficiency of effector cells. Thus, releasing effector cells from the cancer immunosuppressive microenvironment and improving their effective time and functional status in vivo would seem to be ideal strategies for facilitating immunotherapy. Low-dose cyclophosphamide administration can effectively break immunotolerance by inhibiting regulatory T cells. In the present study, in order to verify whether the persistence, distribution and function of effector cells can be improved by inhibiting immunosuppressive microenvironment, low-dose cyclophosphamide was previously intraperitoneally injected into melanoma-bearing C57BL/6 mice, thereafter, CFSE-labeled cytotoxic T lymphocytes were transfused intravenously, and their effective time, distributive pattern, and killing efficiency in different groups were observed by measuring the fluorescence intensity and cell cycle of cytotoxic T lymphocytes distributed in various organs, in comparison with tumor growth. We found down-regulating Tregs in vivo can simultaneously reduce the levels of interleukin-10 and transforming growth factor-β. Migration and distribution of cytotoxic T lymphocytes in vivo was found to vary with time. Inhibition of immunotolerance can significantly improve the persistence, distribution, and function of cytotoxic T lymphocytes. Correspondingly, significantly higher secretion of perforin, granzyme B, IL-2, and IFN-γ in tumor tissues with decreased tumor growth was seen in the cyclophosphamide injection group than in the control group. Our study may provide useful information on the cyclophosphamide-mediated mechanism for facilitating tumor immunotherapy by inhibiting the immunosuppressive tumor microenvironment.

Search for lepton flavour violation in the eμ continuum with the ATLAS detector in [Formula: see text]pp collisions at the LHC

This paper presents a search for the t-channel exchange of an R-parity violating scalar top quark ([Formula: see text]) in the e±μ∓ continuum using 2.1 fb-1 of data collected by the ATLAS detector in [Formula: see text]pp collisions at the Large Hadron Collider. Data are found to be consistent with the expectation from the Standard Model backgrounds. Limits on R-parity-violating couplings at 95 % C.L. are calculated as a function of the scalar top mass ([Formula: see text]). The upper limits on the production cross section for pp→eμX, through the t-channel exchange of a scalar top quark, ranges from 170 fb for [Formula: see text] to 30 fb for [Formula: see text].

Determination of carrier-envelope phase of relativistic few-cycle laser pulses by Thomson backscattering spectroscopy

A method is proposed to determine the carrier-envelope phase (CEP) of a relativistic few-cycle laser pulse via the frequency of the Thomson backscattering (TBS) light. We theoretically investigate the generation of a flying mirror when a few-cycle drive pulse with relativistic intensity interacts with a target combined with a thin and a thick foil. The frequency of the TBS light generated from the flying mirror shows a sensitive dependence on the CEP of the drive pulse. The obtained results are verified by one-dimensional particle-in-cell simulations and are explained by an analytical model.

Measurement of the ZZ production cross section and limits on anomalous neutral triple gauge couplings in proton-proton collisions at sqrt[s] = 7 TeV with the ATLAS detector

A measurement of the ZZ production cross section in proton-proton collisions at sqrt[s] = 7 TeV using data corresponding to an integrated luminosity of 1.02 fb(-1) recorded by the ATLAS experiment at the LHC is presented. Twelve events containing two Z boson candidates decaying to electrons and/or muons are observed, with an expected background of 0.3 ± 0.3(stat)(-0.3)(+0.4)(syst) events. The cross section measured in a phase-space region with good detector acceptance and for dilepton masses within the range 66 to 116 GeV is σ(ZZ → ℓ+ ℓ- ℓ+ ℓ-)(fid) = 19.4(-5.2)(+6.3)(stat)(-0.7)(+0.9)(syst) ± 0.7(lumi) fb. The resulting total cross section for on-shell ZZ production, σ(ZZ)(tot) = 8.5(-2.3)(+2.7)(stat)(-0.3)(+0.4)(syst) ± 0.3(lumi) pb, is consistent with the standard model expectation of 6.5(-0.2)(+0.3) pb calculated at the next-to-leading order in QCD. Limits on anomalous neutral triple gauge boson couplings are derived.

Relativistic single-cycled short-wavelength laser pulse compressed from a chirped pulse induced by laser-foil interaction

By particle-in-cell simulation and analysis, we propose a plasma approach to generate a relativistic chirped pulse based on a laser-foil interaction. When two counterpropagating circularly polarized pulses interact with an overdense foil, the driving pulse (with a larger laser field amplitude) will accelerate the whole foil to form a double-layer structure, and the scattered pulse (with a smaller laser field amplitude) is reflected by this flying layer. Because of the Doppler effect and the varying velocity of the layer, the reflected pulse is up-shifted for frequency and chirped; thus, it could be compressed to a nearly single-cycled relativistic laser pulse with a short wavelength. Simulations show that a nearly single-cycled subfemtosecond relativistic pulse can be generated with a wavelength of 0.2 μm after dispersion compensation.

Generating quasi-single-cycle relativistic laser pulses by laser-foil interaction

A scheme for producing nearly single-cycle relativistic laser pulses is proposed. When a laser pulse interacts with an overdense thin foil, because of self-consistent nonlinear modulation, the latter will be more transparent to the more intense part of the laser, so that a transmitted pulse can be much shorter than the incident pulse. Using two-dimensional particle-in-cell simulation and analytical modeling, it is found that a transmitted pulse of duration 4 fs and peak intensity 3 x 10{20} W/cm{2} can be generated from a circularly polarized laser pulse. The intensity of the resulting pulse is only limited by that of the incident pulse, since this scheme involves only laser-plasma interaction.