Prone Position in Treatment of Hypoxemia in Patients Who Underwent Type A Aortic Dissection Surgery.

BACKGROUND: Postoperative hypoxemia is a high-risk complication after acute type A aortic dissection (TAAD) surgery. Prone position (PP) is an effective treatment for acute respiratory failure, which may improve the gas exchange of the injured lung and the patient's survival. PP is reported to improve the respiratory condition after cardiac surgery. However, limited data exist on the effect of PP in patients who underwent acute TAAD surgery. METHODS: We retrospectively analyzed the clinical outcomes of seven patients with severe hypoxemia who underwent PP after acute TAAD surgery. The results of arterial blood gas, chest X-ray, and survival were collected. RESULTS: Seven patients (3 female, mean age 48.3±11.7 years) were recruited in this study. All patients received total arch replacement and frozen elephant trunk implantation procedure. The PaO2 at day 1 after PP was higher than before PP (126.3±49.3 vs. 77.8±15.5 mmHg). The oxygenation index rose sharply from 83.0 (80.0, 87.0) to 188.3±56.5 at day 3 after PP. There was no significant difference in heart rate between before and after PP procedure. Chest X-ray showed the diffuse shadow was significantly improved after PP. All patients responded well to PP, and all patients were discharged except for one patient, who died perioperatively due to multiple organ failure. CONCLUSIONS: PP is a safe and feasible option for severe hypoxemia patients after TAAD surgery.

Insights into the functional divergence of the haloacid dehalogenase superfamily from phosphomonoesterase to inorganic pyrophosphatase.

The evolution of enzyme catalytic structures and mechanisms has drawn increasing attention. In this study, we investigate the functional divergence from phosphomonoesterase to inorganic pyrophosphatase in the haloacid dehalogenase (HAD) superfamily. In this study, a series of models was constructed, and calculations were performed by using density functional theory with the B3LYP functional. The calculations suggest that in most HAD members, the active-site structure is unstable due to the binding of the substrate inorganic pyrophosphate (PPi), and reactions involving PPi cannot be catalyzed. In BT2127, which is a unique member of the HAD superfamily, the Mg2+-coordinating residues Asn172 and Glu47 play a role in stabilizing the active-site structure to adapt to the substrate PPi by providing much stronger coordination interactions with the Mg2+ ion. The calculation results suggest that Asn172 and Glu47 are crucial in the evolution of the inorganic pyrophosphatase activity in the HAD superfamily. Our study provides definitive chemical insight into the functional divergence of the HAD superfamily, and helps in understanding the evolution of enzyme catalytic structures and mechanisms.

Evolutionary insights into the active-site structures of the metallo-ß-lactamase superfamily from a classification study with support vector machine.

The metallo-ß-lactamase (MßL) superfamily, which is intriguing due to its enzyme promiscuity, is a good model enzyme superfamily for studies of catalytic function evolution. Our previous study traced the evolution of the phosphotriesterase activity of the MßL superfamily and found that MßLs go through three typical active-site structures in the development of phosphotriesterase activity. In the present study, taking the three typical active-site structures as class labels, the classification and prediction models, which were established by support vector machine and amino acid composition, classified the MßL members into three classes. The indispensable amino acid compositions showed a surprising performance that was remarkably better than the performance of the dispensable amino acid compositions and even equal to the performance of the 20 native amino acids. We further traced the origin of the classification error and found that there was one subclass adopting a type of active-site structure that was the evolutionary transition between these classes. After that, our classification and prediction models were successfully used to predict several MßL active-site structures that lost the dinuclear structures during crystallization. In summary, our studies established a classification and prediction system for active-site structures that well compensated for experimental methods that recognize protein structure details and suggest that the indispensable amino acids contain much more protein structure information than the dispensable amino acids.

Abnormal blood pressure circadian rhythms are relevant to cerebral infarction and Leukoaraiosis in hypertensive patients.

BACKGROUND: To investigate the relationships between blood pressure (BP) circadian rhythms and acute cerebral infarction (ACI), silent cerebral infarction (SCI) and the severity of leukoaraiosis in hypertensive patients. METHODS: A retrospective case-control study was performed among hypertensive patients with 24-h ambulatory blood pressure monitoring (ABPM) and cranial magnetic resonance imaging (MRI). RESULTS: A total of 1267 patients were enrolled. Lower nocturnal blood pressure (BP) decreases were observed in ACI patients than in controls (3.3% vs 8.2%, P<0.001). Reverse-dipper pattern (RD) and non-dipper pattern (ND) were found to be independent risk factors for ACI. In ACI patients, both RD and ND BP circadian rhythms were revealed to be independent risk factors for moderate-severe leukoaraiosis. In addition, in SCI patients, RD (OR = 1.7, 95% CI, 0.9-3.0; P = 0.047) or extreme-dipper pattern (ED) (OR = 2.9, 95% CI, 1.2-7.0; P = 0.015) were found to be independent risk factors for moderate-severe leukoaraiosis. Moreover, the greater the severity of leukoaraiosis was, the higher the ratio of abnormal BP circadian rhythms. CONCLUSION: RD and ND BP circadian rhythms might not only be relevant to the onset of ACI but also correlate with the severity of leukoaraiosis. Thus, when modulating BP with antihypertensive drugs, the BP circadian rhythms, and not merely the BP level, should warrant more attention.

The Association of Nocturnal Blood Pressure Patterns and Other Influencing Factors With Lacunes and Enlarged Perivascular Spaces in Hypertensive Patients.

Purpose: Nocturnal blood pressure dipping patterns have been associated with an increased risk of Cerebral Small Vessel Disease (CSVD), which has not been well-studied. This study is aimed to explore the association of dipping patterns and other factors with lacunes and enlarged perivascular spaces (EPVS) in patients with hypertension. Methods: We enrolled a total of 1,322 patients with essential hypertension in this study. Magnetic resonance imaging (MRI) scans and 24-h ambulatory blood pressure (BP) monitoring were completed. Nocturnal BP decline was calculated, and then dipping patterns were classified. Patients were classified into four groups according to the performance of lacunes and EPVS in the MRI scan for statistical analysis. Results: (1) Nocturnal BP decline showed independent negative correlation with both lacunes and EPVS while mean systolic BP (mSBP) level showed an independent positive correlation with them (P < 0.05). (2) The frequency of reverse-dippers in the control group was significantly lower than that in other groups; the frequency of non-dippers in the lacunes group and EPVS group was significantly lower than that in the control group; the frequency of extreme-dippers in the EPVS group was significantly higher than that in the mixed (lacunes with EPVS) group (P < 0.05). Conclusions: Both mSBP and dipping patterns might play an important role in developing lacunes and EPVS in patients with hypertension.

Higher Burden of Cerebral Small Vascular Disease Predicts Major Adverse Cardiac and Cerebrovascular Events and Is Related to Abnormal Blood Pressure Variability Pattern in Hypertension Patients.

Background and Objectives: The study aims to test the hypotheses that a higher burden of cerebral small vascular disease (CSVD) predicts major adverse cardiac and cerebrovascular events (MACCE) in patients with hypertension (HTN) and that abnormal blood pressure variability (BPV) pattern aggravates total CSVD burden. Methods: We retrospectively reviewed patients with HTN prospectively selected between February 2015 and February 2019 from three participating centers. Patients were included if they had HTN for over 1 year and had at least one MRI feature of CSVD. Independent predictors were found using multivariate logistic regression. Results: Among the 908 patients who finally enrolled in the study, the number of CSVD markers (OR = 1.940; 95% CI = 1.393-2.703; P < 0.001) independently predicted MACCE with acceptable predictive value (C-statistic = 0.730; 95% CI = 0.669-0.791; P < 0.001). An abnormal BPV pattern was identified as an independent risk factor for increased CSVD burden. Among them, reverse-dipper subtype demonstrated the most significant relationship (OR = 1.725; 95% CI = 1.129-2.633; P = 0.012). Conclusion: Total CSVD burden predicts an increased risk of composite MACCE independently. An abnormal BPV pattern is associated with a higher burden of CSVD.

Leukoaraiosis is associated with clinical symptom severity, poor neurological function prognosis and stroke recurrence in mild intracerebral hemorrhage: a prospective multi-center cohort study.

Leukoaraiosis (LA) results from ischemic injury in small cerebral vessels, which may be attributable to decreased vascular density, reduced cerebrovascular angiogenesis, decreased cerebral blood flow, or microcirculatory dysfunction in the brain. In this study, we enrolled 357 patients with mild intracerebral hemorrhage (ICH) from five hospitals in China and analyzed the relationships between LA and clinical symptom severity at admission, neurological function prognosis at 3 months, and 1-year stroke recurrence. Patients were divided into groups based on Fazekas scale scores: no LA (n = 83), mild LA (n = 64), moderate LA (n = 98) and severe LA (n = 112). More severe LA, larger hematoma volume, and higher blood glucose level at admission were associated with more severe neurological deficit. More severe LA, older age and larger hematoma volume were associated with worse neurological function prognosis at 3 months. In addition, moderate-to-severe LA, admission glucose and symptom-free cerebral infarction were associated with 1-year stroke recurrence. These findings suggest that LA severity may be a potential marker of individual ICH vulnerability, which can be characterized by poor tolerance to intracerebral attack or poor recovery ability after ICH. Evaluating LA severity in patients with mild ICH may help neurologists to optimize treatment protocols. This study was approved by the Ethics Committee of Ruijin Hospital Affiliated to Shanghai Jiao Tong University (approval No. 12) on March 10, 2011.

The Predictive Values of Different Small Vessel Disease Scores on Clinical Outcomes in Mild ICH Patients.

AIM: To explore the predictive values of different small vessel disease (SVD) scores on functional recoveries and the clinical cerebrovascular events in mild intracerebral hemorrhage (ICH). METHODS: In this study, we enrolled conscious and mild ICH patients without surgery and further divided them into the cerebral amyloid angiopathy (CAA)-ICH group and hypertension (HTN)-ICH group. The severity of individual SVD markers, including lacunes, cerebral microbleeds (CMBs), enlarged perivascular spaces (EPVS), white matter hyperintensity (WMH), and cortical superficial siderosis (cSS), was evaluated. The original SVD score, modified SVD score, refined SVD score, and CAA-SVD score and the total number of SVD markers were further calculated. Functional recoveries were evaluated using the modified Rankin scale. Recurrences of stroke were defined as readmission to the hospital with a definite diagnosis of stroke. RESULTS: A total of 163 ICH patients (60 CAA-ICH and 103 HTN-ICH) were included in the study. The CAA-SVD score (OR=3.429; 95% confidence interval (CI)=1.518-7.748) had the best predictive effect on functional dependence in the CAA-ICH group, among which cSS severities probably played a vital role (OR=4.665; 95% CI=1.388-15.679). The total number of SVD markers [hazard ratio (HR)=3.765; 95% CI=1.467-9.663] can better identify stroke recurrences in CAA-ICH. In HTN-ICH, while the total number of SVD markers (HR=2.136; 95% CI=1.218-3.745) also demonstrated association with recurrent stroke, this effect seems to be related with the influence of lacunes (HR=5.064; 95% CI=1.697-15.116). CONCLUSIONS: The CAA-SVD score and the total number of SVD markers might identify mild CAA-ICH patients with poor prognosis. However, it would be better to focus on lacunes rather than on the overall burden of SVD to predict recurrent strokes in HTN-ICH.

The Single Nucleotide Polymorphisms of Chromosome 9p21 and CD147 Were Relevant with the Carotid Plaque Risk in Acute Cerebral Infarction Patients Among Chinese Han Population.

This study focused on the relevance between the carotid plaque formation and the single nucleotide polymorphisms of chromosome 9p21 and CD147 in acute non-cardiogenic cerebral infarction. A total of 937 eligible patients were enrolled and categorized into carotid plaque group or non-carotid plaque group. The baseline data was analyzed, and the SNPs of chromosome 9p21 and CD147 were detected. After analyzing the results of clinic data and SNPs, we found that age, total cholesterol, low density lipoprotein, systolic blood pressure, fasting serum glucose, and NIHSS score are associated with plaque formation. Meanwhile, rs10757274, rs4977574, and rs4919862 existed statistical differences between two groups. We also analyzed linkage disequilibrium, haplotype, and inheritance models of these three SNPs, and drew the ROC curve to assess diagnostic efficiency. The results showed that mutations of SNP rs10757274 and rs4977574 in chromosome 9p21 together with SNP rs4919862 located in gene CD147 were highly relevant with the carotid plague formation in acute cerebral ischemia patients. Compared with single SNP genotype mutation, combined allele mutations on rs10757274 or rs4977574 in chromosome 9p21 with rs4919862 in CD147 resulted in much higher risks of patients, which might be associated with acute cerebral infarction happening.

The Presence of Previous Cerebral Microbleeds Has a Negative Effect on Hypertensive Intracerebral Hemorrhage Recovery.

Background and Purpose: Cerebral microbleeds are an intracerebral microangiopathy with bleeding tendency found in intracerebral hemorrhage patients. However, studies about cerebral microbleed effects on the prognosis of hypertensive intracerebral hemorrhage patients are rare. We performed a prospective study to discuss not only the risk factors of cerebral microbleed incidence in hypertensive intracerebral hemorrhage patients but also the relevance of cerebral microbleeds with silent brain infarction, hemorrhage and prognosis. Methods: This study enrolled 100 patients diagnosed with hypertensive intracerebral hemorrhage within 3 days after onset. Magnetic resonance imaging including susceptibility-weighted imaging and diffusion-weighted imaging (DWI) were utilized to examine patients on the fifth day after onset. Regular follow-ups were performed to examine the following clinical cerebrovascular events and vascular deaths in 1 year. Results: Cerebral microbleeds were observed in 55 (55%) patients. Multiple logistic regression analysis showed that over-aging, elevation of serum creatinine, and leukoaraiosis were independently associated with cerebral microbleeds. In addition, higher silent brain infarction prevalence was observed in patients with cerebral microbleeds. In contrast, none of the cerebral microbleed patients exhibited cerebral microbleeds ≥5, which is an independent risk factor of poor 3-month neurological function recovery. During the 1-year follow-up, 14 subjects presented clinical cerebrovascular events or vascular death. The Cox proportional hazards model implicated that atrial fibrillation, cerebral microbleeds ≥5 and silent brain infarction were independent predictive factors for these events. Conclusions: Over-aging combined with an elevation of serum creatinine and leukoaraiosis were independent risk factors of cerebral microbleeds. Patients with cerebral microbleeds were more likely to exhibit silent brain infarction. Poor recovery of 3-month neurological function was observed in hypertensive intracerebral hemorrhage patients with cerebral microbleeds ≥5. Cerebral microbleeds ≥5 or silent brain infarction might also indicate an elevated risk of future cerebrovascular events and vascular death.

Relevance Study on Cerebral Infarction and Resistin Gene Polymorphism in Chinese Han Population.

Recent research on genome-wide associations has implicated that the serum resistin level and its gene polymorphism are associated with cerebral infarction (CI) morbidity and prognosis, and could thereby regulate CI. This study aimed to investigate the association between the resistin single nucleotide polymorphism (SNP) and the susceptibility to CI in the Chinese Han population. A total of 550 CI patients and 313 healthy controls were genotyped. Nine SNPs of the resistin gene previously shown were sequenced and assessed for an association with CI. The numbers of GG genotype carriers of rs3219175 and rs3486119 in the CI group were significantly higher than those in the control group among the middle-aged group (aged 45-65), at 76% vs 67.9% (P=0.025) and 75.5% vs 67.9% (P=0.031). rs3219175 and rs34861192 were associated with CI in the dominant and superdominant models according to the genetic model analysis (P<0.05). Meanwhile, there was strong linkage disequilibrium among the rs34124816, rs3219175, rs34861192, rs1862513, rs3745367, 180C/G and rs3745369 sites. In a haplotype analysis, the occurrence rate of the haplotype AGGCAGC was 1.97 times (P<0.05) higher in the patient group than in the control group. In addition, the numbers of GG genotype carriers of rs3219175 and rs3486119 in the middle-aged male CI patients and the middle-aged small artery occlusion (SAO) CI patients were higher than those in the control group (P<0.05). In the Chinese Han middle-aged population, the GG gene type carriers of the resistin gene sites rs3219175 and rs34861192 had a high risk for CI onset, especially in middle-aged male patients and SAO CI in all middle-aged patients.

Variants on Chromosome 9p21 Confer Risks of Noncardioembolic Cerebral Infarction and Carotid Plaque in the Chinese Han Population.

AIMS: Considering that cerebral infarction (CI) may share a common etiological basis with coronary artery disease (CAD), we evaluated six CAD-related single-nucleotide polymorphisms (SNPs) on 9p21 for investigating the effect of 9p21 on CI or carotid plaque in the Chinese Han population. METHODS: Altogether, 528 patients with noncardioembolic CI (375 with carotid plaque and 153 without carotid plaque) and 258 control subjects were genotyped. Six SNPs previously shown to be associated with CAD were sequenced and assessed for association with CI and carotid plaque using odds ratio (OR) and 95% confidence interval (CI) from logistic regression models. RESULTS: The G allele frequencies of rs2383206 (OR=1.472, p=0.021) and rs4977574 (OR=1.519, p=0.013) significantly increased in patients with CI without carotid plaque compared with middle-aged patients in the control group. The CI risk was higher among the GG genotype carriers than among GA ＋ AA genotype carriers (OR=1.794, 95% CI=1.059-3.039, p=0.030 for rs2383206; OR=1.866, 95% CI=1.088-3.201, p=0.023 for rs4977574). In comparison with the non-GG genotype, the GG genotype of rs2383206 and rs4977574 combined had a 1.733-fold greater risk of CI in the middle-aged group. SNPs rs2383206 and rs4977574 were also associated with a risk of carotid plaque among patients with CI aged ＞ 65 years (OR=2.329, p=0.018 and OR=1.997, p=0.049, respectively). Moreover, six SNPs were strongly correlated with linkage disequilibrium. CONCLUSIONS: Genetic variations of rs2383206 and rs4977574 on 9p21 are potentially associated with CI and carotid plaque in the Chinese Han population. Our results provide further evidence that the 9p21 region represents a major risk locus for cerebrovascular diseases.

[Greenhouse gases fluxes of biological soil crusts and soil ecosystem in the artificial sand-fixing vegetation region in Shapotou area].

Uncertainties still existed for evaluating greenhouse gases fluxes (GHGs), including carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) at the regional scale for desert ecosystem because available GHGs data about biological soil crusts (BSCs) was very scarce. In 2011 and 2012, soil ecosystem covered by various types of BSCs and BSCs at different succession stages in an artificial sand-fixing vegetation region established in various periods at southeast of the Shapotou area in Tengger Desert was selected to measure fluxes of CO2, CH4 and N2O using static chamber and gas chromatography. The results showed that curst type, recovery time and their interactions with sampling date significantly affected CO2 flux. Recovery time and interaction of crust type and sampling date significantly affected CH4 flux. Sampling date significantly affected the fluxes of CO2, CH4 and N2O. The mean annual flux of CO2 for moss crust (105.1 mg x m(-2) x h(-1)) was significantly higher than that of algae crust (37.7 mg x m(-2) x h(-1)) at the same succession stage. Annual mean CH4 and N2O consumption was 19.9 and 3.4 microg x m(-2) x h(-1), respectively. Mean annual consumption of CH4 and N2O for algae crust was slightly higher than that of moss crust, however, significant difference was not found. Ecosystem respiration (Re) of desert soil covered by BSCs increased with the recovery process of desert ecosystem, in contrast, consumption of CH4 and N2O decreased. Re of moss crust was more sensitive to temperature and moisture variation than algae crust and Re sensitivity of temperature and moisture gradually increased with the development and succession of BSCs. Both soil temperature and moisture were not the main factor to determine CH4 and N2O fluxes of BSCs-soil in desert ecosystem.

Volume quantification of acute infratentorial hemorrhage with computed tomography: validation of the formula 1/2ABC and 2/3SH.

OBJECTIVE: To compare the accuracy of formula 1/2ABC with 2/3SH on volume estimation for hypertensive infratentorial hematoma. METHODS: One hundred and forty-seven CT scans diagnosed as hypertensive infratentorial hemorrhage were reviewed. Based on the shape, hematomas were categorized as regular or irregular. Multilobular was defined as a special shape of irregular. Hematoma volume was calculated employing computer-assisted volumetric analysis (CAVA), 1/2ABC and 2/3SH, respectively. RESULTS: The correlation coefficients between 1/2ABC (or 2/3SH) and CAVA were greater than 0.900 in all subgroups. There were neither significant differences in absolute values of volume deviation nor percentage deviation between 1/2ABC and 2/3SH for regular hemorrhage (P>0.05). While for cerebellar, brainstem and irregular hemorrhages, the absolute values of volume deviation and percentage deviation by formula 1/2ABC were greater than 2/3SH (P<0.05). 1/2ABC and 2/3SH underestimated hematoma volume each by 10% and 5% for cerebellar hemorrhage, 14% and 9% for brainstem hemorrhage, 19% and 16% for regular hemorrhage, 9% and 3% for irregular hemorrhage, respectively. In addition, for the multilobular hemorrhage, 1/2ABC underestimated the volume by 9% while 2/3SH overestimated it by 2%. CONCLUSIONS: For regular hemorrhage volume calculation, the accuracy of 2/3SH is similar to 1/2ABC. While for cerebellar, brainstem or irregular hemorrhages (including multilobular), 2/3SH is more accurate than 1/2ABC.