Periodic repolarization dynamics for prediction of mortality: a systematic review and meta-analysis

Background

Prediction of death is the philosopher's stone of arrhythmology. The electrophysiology has proven to be an important tool to predict the risk of death. Periodic repolarization dynamics (PRD) is a novel electrocardiographic marker that indicates the sympathetic effect on repolarization. PRD qualifies the low-frequency oscillations of cardiac repolarization instability using high-resolution 12 channel 24-h Holter recording. Several studies showed that PRD was an independent predictor of all-cause mortality and cardiac mortality. However, the prediction value of PRD has not been established.

Purpose

To evaluate the prediction value of PRD as an approach of risk stratification that selects patients at a higher risk of death.

Methods

We conducted electronic searches of MEDLINE (PubMed), Embase, Cochrane Register of Controlled Trials (CENTRAL), Science Citation Index Expanded, WHO International Clinical Trials Registry platform (ICTRP) and ClinicalTrials.gov from inception to January 9th, 2020. We also screened for relevant abstracts from conferences including ACC Annual Scientific Sessions, ESC Congress and Annual Congress of the EHRA for the last five years (2014–2019). The primary outcome was all-cause mortality and secondary outcome was cardiac mortality. We included study with large sample size while more than one study were found based on the same originated population. We extracted data from included studies and reported pooled outcomes as hazard ratios (HRs) with 95% confidential intervals (CI) for time-to-event outcomes using DerSimonian-Laird random-effects model. We did statistical analyses using Stata version 12.0 and R version 3.6.1.

Results

5 studies including 6758 patients met all selection criteria for our meta-analysis. Follow-up period ranged from 20.4 to 75.1 months. Among 5 studies, 3 studies considered PRD as dichotomous variable and the cut-off value was 5.75 deg2, while 2 studies considered PRD as continuous variable and coefficient was expressed in standardized units (increase per standard deviation). We did subgroup analysis according to the type of variable because of heterogeneity. There was a significant higher risk of all-cause mortality in PRD ≥5.75 deg2 patients compared with PRD <5.75 deg2 patients (HR 2.37, 95% CI 1.77–3.17). As for continuous variable, increased PRD was a predictor for all-cause death (HR 1.28, 95% CI 1.14–1.42) (Figure). The cardiac mortality was significantly increased in patients with PRD ≥5.75 deg2 vs PRD <5.75 deg2 (HR 3.06, 95% CI 1.66–5.65). Increased PRD was associated with cardiac mortality in continuous variable subgroup (HR 1.34, 95% CI 1.21–1.48) (Figure).

Conclusion

Our findings suggest PRD is a significant predictor of all-cause mortality and cardiac mortality. PRD provides new additional electrophysiological indicator for risk stratification until further investigations are available.

Funding Acknowledgement

Type of funding source: None

A prognostic nomogram for event-free survival in patients with atrial fibrillation before cardiac resynchronization therapy

Background

Atrial fibrillation (AF), one of the most common comorbidities with heart failure (HF), is associated with worse prognosis in HF patients receiving cardiac resynchronization therapy (CRT). However, there is still no convenient tool to evaluate and identify patients with high risk of mortality and hospitalization due to heart failure in CRT candidates with AF.

Methods

We included 152 consecutive patients with AF for CRT in our hospital from January 2009 to July 2019. Multivariate Cox regression was applied to derive a nomogram, using multiple imputation for missing values and backward stepwise regression for variable selection.

Results

Five predictors were incorporated in the nomogram, including N-terminal pro brain natriuretic protein (NTproBNP) >1745pg/mL, history of syncope, previous pulmonary hypertension (PHP), moderate or severe tricuspid regurgitation (TR), thyroid stimulating hormone (TSH) >4mIU/L. Concordance index (0.70, 95% CI 0.62–0.77), corrected concordance index (0.67, 95% CI 0.59–0.74) and calibration curve showed optimal discrimination and calibration of the established nomogram. Significant difference of overall event-free survival was recognized by the nomogram-derived scores in patients with high risk (>50 points), intermediate risk (21–50 points) and low risk (0–20 points) before CRT.

Conclusion

Our nomogram may be an applicable tool for early risk stratification among CRT candidates with AF.

Nomogram and risk stratification

Funding Acknowledgement

Type of funding source: None

Stillbirths in China: a nationwide survey

Objective

To estimate a stillbirth rate at 24 or more gestational weeks in 2015–2016 and to explore potentially preventable causes in China.

Design

A multi‐centre cross‐sectional study.

Setting

Ninety‐six hospitals distributed in 24 (of 34) provinces in China.

Population

A total of 75 132 births at 24 completed weeks of gestation or more.

Methods

COX Proportional Hazard Models were performed to examine risk factors for antepartum and intrapartum stillbirths. Population attributable risk percentage was calculated for major risk factors. Correspondence analysis was used to explore region‐specific risk factors for stillbirths.

Main outcome measures

Stillbirth rate and risk factors for stillbirth.

Results

A total of 75 132 births including 949 stillbirths were used for the final analysis, giving a weighted stillbirth rate of 13.2 per 1000 births (95% CI 7.9–18.5). Small for gestational age (SGA) and pre‐eclampsia/eclampsia increased antepartum stillbirths by 26.2% and 11.7%, respectively. Fetal anomalies increased antepartum and intrapartum stillbirths by 17.9% and 7.4%, respectively. Overall, 31.4% of all stillbirths were potentially preventable. Advanced maternal age, pre‐pregnant obesity, chronic hypertension and diabetes mellitus were important risk factors in East China; low education and SGA were major risk factors in Northwest, Southwest, Northeast and South China; and pre‐eclampsia/eclampsia and intrapartum complications were significant risk factors in Central China.

Conclusions

The prevalence of stillbirth was 13.2 per 1000 births in China in 2015–2016. Nearly one‐third of all stillbirths may be preventable. Strategies based on regional characteristics should be considered to reduce further the burden of stillbirths in China.

Tweetable abstract

The stillbirth rate was 13.2 per 1000 births in China in 2015–2016 and nearly one‐third of all stillbirths may be preventable.

The stillbirth rate was 13.2 per 1000 births in China in 2015–2016 and nearly one‐third of all stillbirths may be preventable.

Transcriptomic analysis identifies early cellular and molecular events by which estrogen disrupts testis differentiation and causes feminization in Xenopus laevis

Extensive studies have shown that estrogenic endocrine-disrupting chemicals (EDCs) can disrupt testis differentiation and even cause feminization in vertebrates. However, little is known about the mechanisms by which estrogenic EDCs disrupt testis differentiation. Here, we employed Xenopus laevis, a model amphibian species sensitive to estrogenic EDCs, to explore the molecular and cellular events by which 17β-estradiol (E2) disrupts testis differentiation and causes feminization. Following waterborne exposure to E2 from stage 45/46, genetically male X. laevis were confirmed to undergo testis differentiation inhibition and ovary differentiation activation at stages 52 and 53, ultimately displaying gonadal feminization at stage 66. Using a time-course RNA sequencing approach, we then identified thousands of differentially expressed transcripts (DETs) in genetically male gonad-mesonephros complexes at stages 48, 50 and 52 (the window for testis differentiation) between E2 treatment and the control. Enrichment analysis suggests alterations in cell proliferation, extracellular matrix, and cell motility following E2 exposure. Further verification by multiple methods demonstrated that E2 inhibited cell proliferation, disrupted extracellular matrix, and altered cell motility in the genetically male gonads compared with controls, implying that these events together contributed to testis differentiation disruptions and feminization in X. laevis. This study for the first time uncovered some of the early molecular and cellular events by which estrogen disrupts testicular differentiation and causes feminization in X. laevis. These new findings improve our understanding of the mechanisms by which estrogenic EDCs disrupt testicular differentiation in vertebrates.

Genomic characterization of closely related species in the Rumoiensis clade infers ecogenomic signatures to non-marine environments

Members of the family Vibrionaceae are generally found in marine and brackish environments, playing important roles in nutrient cycling. The Rumoiensis clade is an unconventional group in the genus Vibrio, currently comprising six species from different origins including two species isolated from non-marine environments. In this study, we performed comparative genome analysis of all six species in the clade using their complete genome sequences. We found that two non-marine species, Vibrio casei and Vibrio gangliei, lacked the genes responsible for algal polysaccharide degradation, while a number of glycoside hydrolase genes were enriched in these two species. Expansion of insertion sequences was observed in V. casei and Vibrio rumoiensis, which suggests ongoing genomic changes associated with niche adaptations. The genes responsible for the metabolism of glucosylglycerate, a compound known to play a role as compatible solutes under nitrogen limitation, were conserved across the clade. These characteristics, along with genes encoding species-specific functions, may reflect the habit expansion which has led to the current distribution of Rumoiensis clade species. Genome analysis of all species in a single clade give us valuable insights into the genomic background of the Rumoiensis clade species and emphasize the genomic diversity and versatility of Vibrionaceae.

Diagnostic potential of urinary monocyte chemoattractant protein-1 for Alzheimer's disease and amnestic mild cognitive impairment

BACKGROUND AND PURPOSE

The chemokine monocyte chemoattractant protein-1 (MCP-1) is involved in the pathogenesis of Alzheimer's disease (AD). This study aimed to investigate whether urinary MCP-1 can distinguish patients with AD, patients with amnestic mild cognitive impairment (aMCI) and cognitively normal (CN) subjects.

METHODS

A total of 754 participants, including 97 patients with AD, 50 patients with aMCI and 84 age- and sex-matched CN controls as well as a cohort of 523 CN subjects of different ages, were enrolled from five hospitals located in different areas of China. Urinary MCP-1 levels were determined using enzyme-linked immunosorbent assays. The correlations between urinary MCP-1 levels and cognition test scores or age were analysed. The optimal diagnostic sensitivity and specificity were determined using receiver operating characteristic curve analysis.

RESULTS

In the cohort of CN subjects of different ages, urinary MCP-1 levels increased with ageing and were correlated with age. The urinary MCP-1 levels were higher in females than in males. In the cohort composed of patients with AD, aMCI and age- and sex-matched CN controls, urinary MCP-1 levels were significantly higher in patients with AD and aMCI than in CN controls. There were no differences in urine MCP-1 levels between the AD group and the aMCI group. The urinary MCP-1 levels were correlated with the Mini-Mental State Examination scores and age, and were able to differentiate patients with AD and aMCI from CN subjects.

CONCLUSIONS

Urinary MCP-1 is a potential biomarker for the diagnosis of AD and aMCI.

Evaluation of the effects of low concentrations of bisphenol AF on gonadal development using the Xenopus laevis model: A finding of testicular differentiation inhibition coupled with feminization

Developmental exposures to estrogenic chemicals possibly cause structural and functional abnormalities of reproductive organs in vertebrates. Bisphenol AF (BPAF), a bisphenol A (BPA) analogue, has been shown to have higher estrogenic activity than BPA, but little is known about the effects of BPAF on gonadal development, particularly gonadal differentiation. We aimed to determine whether low concentrations of BPAF could disrupt gonadal differentiation and subsequent development using Xenopus laevis, a model species for studying feminizing effects of estrogenic chemicals. X. laevis tadpoles were exposed to BPAF (1, 10, 100 nM) or 17β-estradiol (E2, positive control) from stages 45/46 to 53 and 66 in a semi-static exposure system, with a prolonged treatment with the highest concentration to the eighth week post-metamorphosis (WPM8). Gonadal morphology and histology as well as sexually dimorphic gene expression were examined to evaluate the effects of BPAF. All concentrations of BPAF caused changes in testicular morphology at different developmental stages compared with controls. Specifically, at stage 53, BPAF like E2 resulted in decreases in both the size and the number of gonadal metameres (gonomeres) in testes, looking like ovaries. Some of BPAF-treated testes remained segmented and even became discontinuous and fragmented at subsequent stages. Histological abnormalities were also observed in BPAF-treated testes, such as ovarian cavity at stages 53 and 66 and poorly developed seminiferous tubules on WPM8. At the molecular level, BPAF inhibited expression of male highly expressed genes in testes at stage 53. Correspondingly, BPAF, like E2, inhibited cell proliferation in testes at stage 50. All results show that low concentrations of BPAF inhibited testicular differentiation and subsequent development in X. laevis, along with feminizing effects to some degree. Our finding implies a risk of BPAF to the male reproductive system of vertebrates including humans.

Peptidyl-Lys metalloendopeptidase (Lys-N) purified from dry fruit of Grifola frondosa demonstrates "mirror"digestion property with lysyl endopeptidase (Lys-C)

RATIONALE

Lys-N, also known as lysine-specific metalloendopeptidase, functions as the "sister" enzyme of lysyl endopeptidase (Lys-C) in proteomic research. Its digestion specificity at the N-terminal lysine residue makes it a very useful tool in proteomics analysis, especially in mass spectrometry (MS)-based de novo sequencing of proteins.

METHODS

Here we present a complete production process of highly purified Lys-N from dry fruit of Grifola frondosa (maitake mushroom). The purification process includes one step of microfiltration plus one step of UF/DF (ultrafiltration used in tandem with a diafiltration method) recovery and four steps of chromatographic purification.

RESULTS

The overall yield of the process was approximately 6.7 mg Lys-N protein/kg dry fruit of G. frondosa. The assay data demonstrated that the purified Lys-N exhibited high enzymatic activity and specificity.

CONCLUSIONS

The novel production process provides for the first time the extraction of Lys-N from dry fruit of G. frondosa. The process is also stable and scalable, and provides an economic way of producing the enzyme in large quantities for MS-based proteomics and other biological studies.

The Predictive Value of Sarcopenia and Its Individual Criteria for Cardiovascular and All-Cause Mortality in Suburb-dwelling Older Chinese

OBJECTIVES

The aim of the present study is to investigate the associations between the Asian Working Group for Sarcopenia (AWGS) sarcopenic definition, and its individual criteria, and risk of cardiovascular disease (CVD) and all-cause mortality in the Chinese elderly.

METHODS

Longitudinal analysis of 1,264 participants aged 60 years or older at baseline (2013-2014) living in suburban areas, China. Sarcopenia was defined according to the recommended algorithm of AWGS. Muscle mass was measured by a direct segmental multifrequency bioelectrical impedance analysis. Muscle strength was assessed by handgrip strength, and physical performance measured via usual walking speed.

RESULTS

Cox proportional hazard models were used to assess the risk of CVD and all-cause mortality. After 40 months of follow-up, forty-eight deaths (4.2%) died in this cohort. The mortality rate with sarcopenia was 4.7% in men and 3.8% in women. After adjusting for potential confounders, the risk of all-cause death was 4.15 times higher in subjects with sarcopenia. Furthermore, low muscle mass (HR: 2.62, 95% CI 1.34-5.13) and low grip strength (HR: 5.79; 95% CI 2.28-14.71), but not walking speed, were found to be significantly associated with all-cause mortality. Risk of CVD mortality was significantly greater in sarcopenia. Low grip strength and low walking speed were associated with 11 times (HR: 11.03, 95% CI 1.58-77.02) and 13 times (HR: 13.02; 95% CI 1.18-143.78) higher risk of CVD mortality.

CONCLUSIONS

Sarcopenia and components of sarcopenia were associated with greater CVD and all-cause mortality. Pertinent prevention or rehabilitation programs projects should look to promote healthy aging in different types of sarcopenia group.

[Clinical application of two extraction methods of impacted teeth combined with immediate implantation]

PURPOSE

To observe the effects of immediate implantation combined with high-speed turbine minimally invasive technology and traditional technology on postoperative analgesia, mouth opening and alveolar bone resorption after removal of complex impacted teeth.

METHODS

Eighty patients with impacted teeth treated in our hospital from January 2014 to December 2018 were randomly divided into 2 groups: experimental group and control group with 40 cases in each group. Patients in the experimental group were treated with high-speed turbine minimally invasive surgery combined with immediate implantation, while patients in the control group were treated with traditional surgery combined with immediate implantation. Differences in alveolar bone resorption, pain, swelling, limited mouth opening, intact extraction socket and complications were compared between the two groups. SPSS 19.0 software package was used to perform statistical analysis.

RESULTS

Three months after operation, the implant height of the maxillary anterior teeth, maxillary molar, mandibular anterior teeth and mandibular molar areas in the experimental group was significantly lower than that in the control group. One day after operation, the VAS score of the experimental group was significantly lower than that of the control group (P<0.05). Three months after operation,there was no significant difference in VAS score between the two groups (P>0.05); but intact extraction socket, swelling degree and mouth opening limitation of the experimental group were significantly lower than those of the control group. The root fracture, adjacent teeth loosening, gingival tear, lingual bone plate fracture of the experimental group were significantly lower than those of the control group.

CONCLUSIONS

High-speed turbine minimally invasive treatment combined with immediate implantation after extraction of complex impacted teeth can significantly increase alveolar bone resorption, relieve swelling and preserve intact extraction socket, reduce pain and complications after operation. It is recommended to be popularized in clinic.

Porcine insulin receptor substrate 2: molecular cloning, tissues distribution, and functions in hepatocyte and aortic endothelial cells

Insulin receptor substrate 2 (IRS-2) modulates the phosphatidylinositol 3-kinase (PI3K)/Akt pathway, which controls the suppression of gluconeogenic genes; IRS-2 is also a critical node of insulin signaling. Because of the high homology between pig and human IRS-2, we investigated the expression pattern and function of porcine IRS-2. QPCR and immunoblotting were used to detect the IRS-2 expression level in different tissues. There were high IRS-2 levels in the cerebral cortex, hypothalamus, and cerebellum in the central nervous system. In peripheral tissues, IRS-2 was expressed at relatively high levels in the liver. Immunohistochemistry analysis revealed that IRS-2 was mainly distributed in the hypothalamus and cerebral cortex. Furthermore, IRS-2 knockdown porcine hepatocytes and porcine aortic endothelial cells (PAECs) were generated. The IRS-2 knockdown induced abnormal expression of genes involved in glycolipid metabolism in hepatocytes and reduced the antiatherosclerosis ability in PAECs. In addition, we disrupted IRS-2 in porcine embryonic fibroblasts (PEFs) using the CRISPR/Cas9 genome editing system, before finally generating IRS-2 knockout embryos by somatic cell nuclear transfer (SCNT). Taken together, our results indicate that IRS-2 might be a valuable target to establish diabetes and vascular disease models in the pig.

[Early postoperative complications and risk factors in laparoscopic D2 radical gastrectomy for gastric cancer]

Objective: To investigate the morbidity and treatment of early postoperative complications after laparoscopic D2 radical gastrectomy for gastric cancer, and to explore the risk factors. Methods: A case-control study was performed to retrospectively collect clinicopathological data of 764 patients undergoing laparoscopic D2 radical gastrectomy for gastric cancer at our department between January 2015 and December 2017. Patient inclusion criteria: (1) gastric cancer diagnosed by preoperative electronic gastroscopy and biopsy, and confirmed by postoperative pathology; (2) without invasion into adjacent organs by preoperative evaluation of tumors; (3) tumors without definite liver and distant metastasis; (4) R0 resection of gastric cancer and standard D2 lymph node dissection; (5) patients with informed consent. Exclusion criteria: (1) unperformed laparoscopic D2 radical resection; (2) other types of gastric tumor confirmed by pathology; (3) cases with incomplete clinical data. Complication occurring within two weeks after laparoscopic D2 gastrectomy was defined as early postoperative complication. Patients were divided into two groups: non-complication group (693 cases) and complication group (71 cases) according to the occurrence of complications after operation. The clinicopathological data of two groups were analyzed and compared with t test and χ(2) test, and the factors of P < 0.2 were included in the multivariate logistic regression model to analyze the risk factors of postoperative complications. Results: Of 764 patients, 71 (9.3%) developed early postoperative complications, with median onset time of 3 (1 to 11) days. Surgical complications accounted for 7.9% (60/764), including 13 cases (1.7%) of abdominal hemorrhage, 12 cases (1.6%) of anastomotic leakage, 10 cases (1.3%) of incision infection, 8 cases (1.0%) of anastomotic bleeding, 7 cases (0.9%) of gastric stump weakness, 4 cases (0.5%) of abdominal infection, 4 cases (0.5%) of duodenal stump leakage and 2 cases (0.3%) of small intestinal obstruction. Non-surgical complications accounted for 1.4% (11/764), including 6 cases (0.8%) of pulmonary infection and 5 cases (0.7%) of cardiovascular disease. Two cases (0.3%) died of sepsis caused by severe abdominal infection; 9 cases (1.2%) recovered after receiving the second operation, among whom 5 cases were abdominal hemorrhage, 2 cases were anastomotic leakage and 2 cases were duodenal stump leakage; the remaining patients were healed with conservative treatment. Compared with patients without complications, patients with complications had higher proportions of BMI ≥24 kg/m(2) [42.3% (30/71) vs. 24.2%(168/693), χ(2)=10.881, P=0.001], comorbity [64.8% (46/71) vs. 33.5% (232/693), χ(2)=27.277, P<0.001], combined organ resection [70.4% (50/71) vs. 20.5% (142/693), χ(2)=85.338, P<0.001], and pTNM stage of III [70.4% (50/71) vs. 40.1% (278/693), χ(2)=24.196, P<0.001], meanwhile had longer time to postoperative flatus [(4.2±2.1) days vs. (2.9±1.2) days, t=4.621, P=0.023], longer hospital stay [(34.6±12.6) days vs. (14.2±6.2) days, t=9.862, P<0.001] and higher hospitalization cost [(126.8±64.5) thousand yuan vs. (85.2±35.8) thousand yuan, t=11.235, P<0.001]. Multivariate analysis showed that BMI ≥24 kg/m(2) (OR=3.762, 95% CI: 1.960-8.783, P=0.035), accompanying disease (OR=8.620, 95% CI: 1.862-29.752, P<0.001), combined organ resection (OR=6.210, 95% CI: 1.357-21.568, P=0.026), and pTNM stage (OR=4.752, 95% CI: 1.214-12.658, P<0.001) were the independent risk factors of postoperative complications. Conclusions: Laparoscopic D2 radical gastrectomy is a safe and effective approach for gastric cancer. Most early postoperative complications can obtain satisfactory efficacy after conservative treatment. Perioperative management should be strengthened for those patients with high BMI, accompanying diseases, combined organ resection, and advanced pTNM stage.

[Laparoscopic versus open surgery for gastric gastrointestinal stromal tumors in unfavorable location: a propensity score-matching analysis]

Objective: To investigate the efficacy and feasibility of laparoscopic resection for gastric gastrointestinal stromal tumor (GIST) in unfavorable location by comparing with open surgery. Methods: Clinicopathological and follow-up data of 176 patients with gastric GIST in unfavorable location admitted at Union Hospital, Tongji Medical College, Huazhong University of Science and Technology from January 2005 to December 2017 were analyzed retrospectively. There were 94 males and 82 females, aging of (57.4±12.7) years (range: 20-90 years). Of the 176 patients, 64 underwent laparoscopic surgery (laparoscopic group) and 112 underwent open surgery (open group). One-to-one propensity score matching (PSM) was performed to balance the covariance between laparoscopic group and open surgery group. Before PSM, the differences between the two group in tumor size and modified National Institutes of Health risk classification were significant. After PSM, there were 63 pairs (63 cases in laparoscopic group and 63 cases in open group) and the baseline characteristics were comparable between the two groups(P>0.05). The difference of short-term outcome between the two groups were compared using t test, χ(2) test or Wilcoxon rank-sum test. The survival curve was established by Kaplan-Meier method and the Log-rank test was used to compare the survival of the two groups. Results: The operation time of laparoscopic group was shorter ((141.6±100.6) minutes vs. (100.4±67.7) minutes, t=2.681, P=0.008), the hospitalization cost was higher ((5.2±0.7) ten thousand yuan vs. (4.2±0.8) ten thousand yuan, t=7.357, P=0.000) than open group. The time to first flatus ((49.1±8.2) hours vs. (71.0±4.6) hours, t=-18.482, P=0.000) and preoperative hospital stay ((10.3±6.0) days vs. (14.8±7.6) days, t=-3.717, P=0.000) was shorter in laparoscopic group. With a median follow-up time of 44 months (range: 10 to 154 months), the 1-, 3-, 5-year relapse-free survival rates in the laparoscopic group and open group were 98.3%, 92.1%, 92.1% and 100%, 86.3%, 83.2%, respectively (χ(2)=0.696, P=0.404). The 1-, 3-, 5-year overall survival rates in the laparoscopic group and open group were 96.6%, 94.7%, 94.7% and 100%, 91.1%, 81.4%, respectively (χ(2)=0.366, P=0.545). Conclusions: In experienced medical centers, laparoscopic resection is safe and feasible for GIST in unfavorable location. Compared to open surgery, laparoscopic resection achieves a faster postoperative recovery and a similar long-term prognosis.

Activation of cannabinoid receptor 1 is involved in protection against mitochondrial dysfunction and cerebral ischaemic tolerance induced by isoflurane preconditioning

Background

Isoflurane preconditioning (IPC) induces cerebral ischaemic tolerance, but the mechanism remains poorly understood. The aim of this study was to determine changes in mitochondrial function in the brain after IPC, and whether the cannabinoid receptor 1 (CB1R) could be involved in the mechanism of mitochondrial protection mediated by IPC.

Methods

Adult male Sprague-Dawley rats were pretreated with isoflurane 2% for 1 h day -1 , for 5 days consecutively, and then subjected to 120 min right middle cerebral artery occlusion. Cannabinoid receptor 1 expression in the cellular and mitochondrial membrane was measured. The CB1R agonist HU-210 was administered alone, or the antagonists AM251 and SR141716A were given to the animals before each preconditioning. Neurological scores, infarct volume, apoptosis, and mitochondrial function were examined after middle cerebral artery occlusion.

Results

Expression of CB1R on cellular and mitochondrial membranes was increased 6 h after preconditioning. Both IPC and HU-210 administration before middle cerebral artery occlusion improved neurological outcomes and reduced infarct volume. Isoflurane preconditioning increased the expression of the anti-apoptotic proteins Bcl-2 and Bcl-X L and reduced apoptosis in neurones. Isoflurane preconditioning and HU-210 also markedly preserved the activity of respiratory chain complexes, reduced mitochondrial radical generation, preserved mitochondrial membrane potential, and inhibited mitochondrial permeability transition pore opening. Cannabinoid receptor 1 antagonists abolished the improvement in mitochondrial function and the neuroprotective effects induced by IPC.

Conclusions

Our results indicate that IPC elicits brain ischaemic tolerance and mitochondrial protection by activating the CB1R, which provides a new mechanism for IPC-induced neuroprotection against cerebral ischaemia.

[Clinical characteristics and risk factors in pregnancy with severe community-acquired pneumonia]

Objective: To analyze clinical characteristics of severe community-acquired pneumonia during pregnancy and its outcomes, and to explore the relevant risk factors. Methods: From September 2012 to September 2017, 324 398 pregnancies admitted in 7 tertiary hospitals were included. Clinical data of 33 cases of pregnancies with severe community-acquired pneumonia (severe pneumonia group) and 214 cases of pregnancies with common community-acquired pneumonia (control group) were reviewed retrospectively, including the clinical information, manifestations, laboratory examinations and pregnancy outcomes. Relevant risk factors were analyzed by multivariate logistic regression analysis. Results: (1) General data: pregnancies with severe community-acquired pneumonia accounted for 0.010% (33/324 398) of hospitalized pregnancies, the gestational age of two groups were (28±8) and (23±8) weeks, body mass index were (21.7±2.1) and (25.5±3.4) kg/m(2), rate of low income were 54.5% (18/33) and 31.8% (68/214) , respectively. The differences between two groups were all statistically significant (all P<0.05). No significant differences were found in age, pregnancy and parity times, rate of main pregnant complications such as diabetes and hypertension, educational level, asthma and onset seasons between two groups (all P>0.05). (2) Clinical data: the severe pneumonia group had significantly higher incidence of fever [100.0% (33/33) vs 75.2% (161/214) ], shortness of breath (90.9% vs 16.8%) compared with the control group (all P<0.05) .The median peripheral leukocytes counts were 12.3×10(9)/L and 10.2×10(9)/L, the hemoglobin level were (84±18) and (107±14) g/L,the albumin level were (26±4) and (37±3) g/L, the median serum urea nitrogen level were 3.7 and 2.4 mmol/L, the serum creatinine level were (72±25) and (45±11) μmol/L, respectively in two groups. The differences were all statistically significant (all P<0.05). No significantly statistical differences were found in coagulation indicator and cardiac function between two groups (all P>0.05). (3) Treatments: in severe pneumonia group, 12 patients (36.4%,12/33) needed invasive mechanical ventilation, 9 patients (27.3%,9/33) needed non-invasive mechanical ventilation, average time of mechanical ventilation was (7±4) days;8 patients (24.2%,8/33) with septic shock needed vasoactive drugs. However, there was no patient in control group needing mechanical ventilation and vasoactive drugs. (4) Pregnant outcomes: one patient (3.0%,1/33) died in the severe pneumonia group, while no death occurred in the control group. The hospital stay between two groups were (15.1±4.1) and (7.0±1.9) days, the rates of abortion and stillbirth between two groups were 42.4% (14/33) and 3.3% (7/214) , the rates of premature were 10/19 and 6.3% (13/207) , the rates of cesarean were 15/19 and 43.0% (89/207) , the rates of low birth weight newborn were 17/19 and 14.0% (29/207) , the rates of infected newborn were 15/19 and 10.1% (21/207) , the birth weights were (2 165±681) and (3 102±400) g, respectively. The differences between two groups were all statistically significant (all P<0.05). (5) Multivariate logistic regression analysis demonstrated that anemia, low body mass index, hypoproteinemia were risk factors for severe pneumonia in pregnancy (all P<0.05) . Conclusions: Pregnancy with severe community-acquired pneumonia may be complicated by multiple organ dysfunctions, lead to adverse outcomes. Anemia, malnutrition are risk factors for pregnancy with severe pneumonia. Active and effective treatment may improve its prognosis.