C-terminal-truncated hepatitis B virus X protein promotes hepatocarcinogenesis by activating the MAPK pathway.

PURPOSE: C-terminally truncated hepatitis B virus X (ctHBx) is frequently detected in hepatocellular carcinoma (HCC) patients with hepatitis B virus (HBV) integrated into their genomes, but the molecular mechanisms of ctHBx-related oncogenic signaling remain unclear. In this study, the effects of ctHBx on HepG2 cells were investigated by measuring ctHBx-induced changes in the cell cycle-related target proteins cell division cycle 25C (cdc25C) and p53 downstream of the mitogen-activated protein kinase (MAPK) pathway. MATERIALS AND METHODS: ctHBx lentiviruses were constructed and transfected into HepG2 cells. Then, we investigated HepG2 cell line function by conducting the Cell Counting Kit-8 (CCK8) assay, clone formation assay, scratch wound testing, Transwell assays and flow cytometry to examine cell cycle and apoptosis. Western blotting (WB) was performed to detect proteins related to and downstream of the extracellular signal-regulated kinase(ERK)/c-Jun N-terminal kinase(JNK)/p38 MAPK pathway, including cdc25C and p53. RESULTS: ctHBx significantly enhanced the proliferation, migration, invasion and colony-forming capability of HepG2 cells. In addition, ctHBx activated the ERK/JNK/p38 MAPK signaling pathway to regulate cell viability by affecting the expression of cyclin-related proteins, including cdc25C and p53. CONCLUSION: The present study demonstrates that ctHBx promote the formation and development of HCC via regulating MAPK/cdc25C and p53 axis. ctHBx should be the driving factor of HBV-induced hepatocarcinogenesis.

Photochemical Aging of Guaiacol by Fe(III)-Oxalate Complexes in Atmospheric Aqueous Phase.

Fe(III)-oxalate complexes are likely abundant in clouds, fogs and aerosol water. They are photoreactive and can act as an important source of reactive oxygen species (·OH, H2O2 and HO2·) in tropospheric aqueous phases. Although the mechanisms involved in ferrioxalate photolysis have been investigated extensively, few kinetic and mechanistic information is available on the aging of dissolved organic compounds by this photochemical system. In this work, the Fe(III)-oxalate mediated photooxidation of guaiacol (GUA), a model for phenolic compounds emitted from biomass burning, was investigated under typical pH conditions of the atmospheric water. The effect of Fe(III) concentration, oxalate concentration and pH on the photooxidation of GUA was studied in detail. Our results revealed that oxalate can inhibit the oxidation of GUA by Fe(III) under the dark condition. However, the iron-catalyzed photooxidation of GUA can be strongly promoted in the presence of oxalate due to the formation of photoactive Fe(III)-oxalate complexes. GUA was rapidly oxidized to form a number of polymeric, functionalized and open-ring products with low volatility. Detailed reaction pathways for the photooxidation of GUA by Fe(III)-oxalate complexes were proposed based on the results of high-resolution mass spectrometry. This work suggests that ferrioxalate photochemistry can play an important role in the transformation of dissolved organics in atmospheric aqueous phases.

Ultrasonographic diagnosis of fetal hemodynamic parameters in pregnant women with diabetes mellitus in the third trimester of pregnancy.

Objective: It was to investigate the diagnosis of fetal hemodynamics in pregnant women with diabetes mellitus in the third trimester of pregnancy by color Doppler ultrasonography. Methods: 55 women with gestational diabetes mellitus (GDM) in the third trimester of pregnancy who were clinically diagnosed and treated in Haian City People's Hospital of Jiangsu Province were selected as the observation group, and 55 pregnant women with normal prenatal examination results were selected as the controls. The hemodynamic parameters of fetal middle cerebral artery (MCA), umbilical artery (UA), and renal artery (RA) were detected, including the ratio of maximum systolic blood flow velocity to end-diastolic blood flow velocity (S/D), resistance index (RI) and arterial pulsation index (PI). Fasting serum levels of maternal patients were collected for detecting Cystain C (Cys C) and homocysteine (Hcy) to analyze the predictive value of serological indexes and target arterial hemodynamics parameters for adverse pregnancy outcome (APO). Results: The results showed that compared with controls, in the observation group, RI, PI, and S/D of MCA and RA increased significantly, while RI, PI and S/D of UA decreased obviously (P < 0.05), the levels of serum Cys C and Hcy were clearly increased (P < 0.05). The APO rate of controls and observation group was 10.91 % and 25.45 %, respectively. It was found that the area under the curve of serum Cys C, Hcy, and the APO predicted by the hemodynamic parameters of fetal MCA, UA, and RA were all greater than 0.75 (P < 0.05). Multiple Logistic regression analysis showed that serum Cys C and Hcy, and the hemodynamic parameters of fetal MCA, UA and RA were correlated with APO (P < 0.05). Conclusion: In summary, maternal blood glucose level can affect fetal hemodynamic parameters. In the third trimester of pregnancy, the changes of blood flow parameters of fetal MCA, UA, RA, and maternal serum Cys C and Hcy levels are helpful to understand fetal status in utero, and can be used to predict APO.

Comparative study of atmospheric brown carbon at Shanghai and the East China Sea: Molecular characterization and optical properties.

The pollution burdens and compositions of atmospheric brown carbon (BrC) that determine their impacts on climate-health-ecosystems have not been well studied, particularly in some mega-economic coastal areas. Herein, atmospheric BrC samples synchronously collected from urban Shanghai (SH) and Huaniao Island (HNI) in the East China Sea during winter were characterized through ultrahigh-performance liquid chromatography-diode array detector-high resolution mass spectrometry (UHPLC-DAD-HRMS). The three polarity-dependent BrC fractions exhibited significant differences in both light absorption and chromophore composition. The average light absorption coefficients of BrC subfractions at 365 nm in SH were 2.6-3.7 times higher than those in HNI. The water-insoluble BrC (WIS-BrC) and humic-likes BrC (HULIS-BrC) dominated the total BrC absorption in SH (45 ± 7 %) and HNI (43 ± 6 %), respectively. Compared with SH, the higher O/Cw, lower molecule conjugation degree, and reduced mass absorption efficiency at 365 nm (MAE365) in HNI imply a potential bleaching mechanism during the transportation oxidation process. Thousands of BrC chromophores were detected at both sites. >20 major chromophores with strong absorption were unambiguously identified in HULIS-BrC and accounted for ∼40 % of the HULIS light absorption at 365 nm at both sites. These chromophores in SH HULIS-BrC featured oxygenated aromatics and nitroaromatics, while alkyl benzenesulfonic acids with emissions from cargo ships were found in HNI HULIS-BrC. Moreover, 22 major chromophores identified in WIS-BrC included alkaloids, polyaromatic hydrocarbons (PAHs), and carbonyl oxygenated PAHs, contributing 39 % and 49 % of the WIS-BrC light absorption at 365 nm in SH and HNI, respectively. Ascertaining the molecular-specific optical properties of BrC chromophores over the mega-economic coastal area is helpful for the predictive understanding of the sources and evolution of BrC, as well as its atmospheric behavior from land to sea.

Association between dietary consumption of fatty acids and age-related macular degeneration in the National Health and Nutrition Examination Survey.

The aim of this study is to assess the relationship between dietary intake of fatty acids and the age-related macular degeneration (AMD) in the United States population. Adult participants of the 2005-2008 National Health and Nutrition Examination Survey (NHANES) were included in this nationwide cross-sectional study. Dietary fatty acid intake was obtained from two 24-h dietary recall interviews. The intake of dietary fatty acids was analyzed as a continuous and categorical variable. AMD status was assessed using nonmydriatic fundus photographs. Univariate and multivariate logistic regression analyses were used to assess the association between dietary fatty acid intake and AMD. The unweighted population included 4702 individuals of whom 374 had AMD. After adjusting for relevant variables, each 1 unit increase (1 mg/1000 kcal) intake of EPA (OR: 0.996, 95% CI: 0.993-0.996, P = 0.018), DPA (OR: 0.976, 95% CI: 0.962-0.990, P = 0.002), and DHA (OR: 0.996, 95% CI: 0.994-0.999, P = 0.003) were significantly decreased odds of any AMD. The highest versus lowest quartile of EPA (OR: 0.476, P for trend < 0.001), DPA (OR: 0.467, P for trend = 0.005) and DHA (OR: 0.586, P for trend = 0.008) were negatively associated with the odds of any AMD. Subgroup analysis showed that higher quartiles of EPA (OR: 0.461, P for trend < 0.002), DPA (OR: 0.467, P for trend = 0.006) and DHA (OR: 0.578, P for trend = 0.007) exhibited a negative association with early AMD. The study found no significant association between the intake of dietary fatty acids, including n-3 PUFA, and the odds of late AMD. In the 2005-2008 NHANES population, higher dietary DHA, DPA and EPA intake associated with decreased odds of early AMD. However, no clear association was found between specific types of FAs and late AMD.

Elucidating contributions of volatile organic compounds to ozone formation using random forest during COVID-19 pandemic: A case study in China.

Ozone has been reported to increase despite nitrogen oxides reductions during the COVID-19 pandemic, and ozone formation needs to be revisited using volatile organic compounds (VOCs), which are rarely measured during the pandemic. Here, a total of 98 VOCs species were monitored in an economy-active city in China from January 2021 to August 2022 to assess contributions to ozone formation during the pandemic. Total VOCs concentrations were 35.55 ± 21.47 ppb during the entire period, among which alkanes account for the largest fraction (13.78 ppb, 38.0%), followed by aromatics (6.16 ppb, 16.8%) and oxygenated VOCs (OVOCs, 5.69 ppb, 15.7%). Most VOCs groups (e.g., alkenes, OVOCs) and individual species (e.g., isoprene, methyl vinyl ketone) display obvious seasonal and diurnal variations, which are related to their sources and reactivities. No weekend effects of VOCs suggest limited influences from traffic emissions during pandemic. Aromatics and alkenes are the major contributors (39% and 33%) to ozone formation potential, largely driven by o/m/p-xylene (21%), ethylene (15%), toluene (9%). Secondary organic aerosol formation potential is dominated by toluene (>50%) despite its low proportion (5%). Further inclusion of VOCs and meteorology in the Random Forest model shows good ozone prediction performance (R2 = 0.77-0.86, RMSE = 11.95-19.91 µg/m3, MAE = 8.89-14.58 µg/m3). VOCs and NO2 contribute >50% of total importance with the largest difference in importance ratio of VOCs/NO2 in the summer and winter, implying ozone formation regime may vary. No seasonal variations in importance of meteorology are observed, while importance of other variables (e.g., PM2.5) is highest in the summer. This work identifies critical VOCs groups and species for ozone formation during the pandemic, and demonstrates the feasibility of machine learning algorithms in elucidation of ozone formation mechanisms.

Computed Tomography Angiography-Based Thrombus Radiomics for Predicting the Time Since Stroke Onset.

RATIONALE AND OBJECTIVES: The measurement of the time since stroke onset (TSS) is crucial for decision-making in the treatment of acute ischemic stroke (AIS). This study assessed the utility of computed tomography angiography (CTA) radiomics features (RFs) to estimate TSS. MATERIALS AND METHODS: A total of 221 patients with AIS were enrolled in this retrospective study and were divided into a training group (n = 154) and a test group (n = 67). Thrombi in CTA images were manually outlined using ITK-SNAP. Images were aligned, normalized, and pre-processed to extract RFs. The TSS was calculated as the time from stroke onset to CTA completion. The patients were classified into two groups according to estimated TSS: ≤4.5 and >4.5 hours. A total of 944 RFs were extracted from CTA images. Clinical factors associated with TSS were identified using multivariate logistic regression, and a combined model (clinical data and RFs) was constructed. The predictive value of the models was assessed by the area under the receiver operating characteristic curve (AUC). The performance of the models was compared using the DeLong test, and clinical utility was evaluated by decision curve analysis. RESULTS: The AUC of the radiomics model was 0.803 (95% confidence interval [CI]: 0.733-0.873) and 0.803 (95% CI: 0.698-0.908) in the training and test cohorts, respectively. The AUC of the combined model (containing data on age, diabetes, and atrial fibrillation) in the training and test sets was 0.813 (95% CI: 0.750-0.889) and 0.803 (95% CI: 0.699-0.907), respectively. The DeLong test showed no significant difference between the radiomics and combined models. Decision curve analysis showed that both models had clinical utility. CONCLUSION: CTA-based thrombus radiomics can estimate TSS in patients with AIS. The addition of clinical data to the model does not improve predictive performance.

Oxidative potential induced by metal-organic interaction from PM2.5 in simulated biological fluids.

The oxidative potential (OP) of fine particulate matter (PM2.5) has recently been proposed as a metric that may prove more indicative of human health effects than the routinely measured PM2.5 concentration. Observations of exposure to PM2.5 show most OP are originated from the contribution of transition metals and organics, but the pertinent coupling mechanisms are unclear. Here, we report laboratory observations in four simulated biological fluids (i.e., simulated saliva, surrogate lung fluid, artificial lysosomal fluid, and synthetic serum) that reveal OP of PM2.5 are significantly induced by prevalent metal complexes formed with nitrogen- and oxygen-containing compounds in low acid environments. Analyses of mass spectra and interaction factors indicate that organic-metal mixture effect in PM2.5, leading to synergistic, additive to antagonistic effects, which may serve as the dominant mechanism for this OP formation. A metal-organic mixtures origin for OP could explain why PM2.5 emission controls should emphasize the reduction of key toxic components, rather than just PM2.5 mass concentration control. SYNOPSIS: This study has investigated the oxidative potential of inhaled atmospheric particulate matter (PM) in four simulated biological fluids, which highlight the importance of metal-organic complexes to the formation of oxidative potential (OP).

Assessment of Primary Collateral Grades Based on the Integrity of Willis' Circle: Predicting the Prognosis of Acute Intracranial Internal Carotid Artery Occlusion Before Thrombectomy.

OBJECTIVE: Endovascular mechanical thrombectomy (EVMT) has shown significant efficacy in improving neurological functions in patients with intracranial internal carotid artery occlusion (IICAO), but its clinical outcomes are variable. We examined the relationship between favorable clinical outcomes after EVMT in IICAO and a set of predictors. METHODS: In this retrospective study, 189 patients with IICAO treated by EVMT at 3 centers from November 2015 to December 2020 were included and analyzed. Non-contrast computed tomography and computed tomography angiography were evaluated on admission. The morphology of IICAO was categorized into Ia, Ib, L, or T types, depending on the involvement of the posterior communicating artery origin, proximal anterior cerebral artery, and middle cerebral artery. The Willis' circle was categorized as integrated or compromised Willis' circle. In combination with the involvement of the IICAO and the integrity of Willis' circle, we used the primary collateral grade (PCG) to describe the presence of functional Willisian collaterals. Baseline data including demographics, characteristics, vascular risk factors, and initial National Institutes of Health Stroke Scale scores were collected. Hemorrhagic transformation was evaluated using the 24-hour non-contrast computed tomography after EVMT. Favorable outcomes based on modified Rankin scale, were defined as 0-2 at 90 days. RESULTS: A total of 189 patients were included (median age, 69 years; 126 male [66.7%]). 104 patients [55.0%] showed reperfusion after EVMT, but 72 patients [38.1%] achieved favorable outcomes at 90 days. The mortality rate of type Ib was significantly higher than that with type Ia (χ2 = 14.21, P = 0.001). The outcome with different structure of Willis' circle was not statistically different between the 2 groups. A multivariate logistic regression analysis showed that IICAO T-type (odds ratio, 0.028 [95% confidence interval: 0.323-3.829], P = 0.042) and PCG 2 (odds ratio 9.427[95% confidence interval:1.863-47.698], P = 0.007) were predictors of favorable outcomes. CONCLUSIONS: Evaluation of PCG by determining the type of IICAO and the integrity of Willis' circle may serve as a valuable indicator for the prognosis and as an essential reference for screening patients before EVMT.

The Abnormal Proliferation of Hepatocytes is Associated with MC-LR and C-Terminal Truncated HBX Synergistic Disturbance of the Redox Balance.

Background: Microcystin-LR (MC-LR) and hepatitis B virus (HBV) are associated with hepatocellular carcinoma (HCC). However, the concentrations of MC-LR in drinking water and the synergistic effect of MC-LR and HBV on hepatocellular carcinogenesis through their disturbance of redox balance have not been fully elucidated. Methods: We measured the MC-LR concentrations in 168 drinking water samples of areas with a high incidence of HCC. The relationships between MC-LR and both redox status and liver diseases in 177 local residents were analyzed. The hepatoma cell line HepG2 transfected with C-terminal truncated hepatitis B virus X gene (Ct-HBX) were treated with MC-LR. Reactive oxygen species (ROS), superoxide dismutase (SOD), glutathione (GSH) and malondialdehyde (MDA) were measured. Cell proliferation, migration, invasion, and apoptosis were assessed with cell activity assays, scratch and transwell assays, and flow cytometry, respectively. The mRNA and protein expression-related redox status genes were analyzed with qPCR and Western blotting. Results: The average concentration of MC-LR in well water, river water and reservoir water were 57.55 ng/L, 76.74 ng/L and 132.86 ng/L respectively, and the differences were statistically significant (P < 0.05). The MC-LR levels in drinking water were correlated with liver health status, including hepatitis, clonorchiasis, glutamic pyruvic transaminase abnormalities and hepatitis B surface antigen carriage (all P values < 0.05). The serum MDA increased in subjects who drank reservoir water and were infected with HBV (P < 0.05). In the cell experiment, ROS increased when Ct-HBX-transfected HepG2 cells were treated with MC-LR, followed by a decrease in SOD and GSH and an increase in MDA. MC-LR combined with Ct-HBX promoted the proliferation, migration and invasion of HepG2 cells, upregulated the mRNA and protein expression of MAOA gene, and downregulated UCP2 and GPX1 genes. Conclusion: MC-LR and HBV may synergistically affect redox status and play an important role in hepatocarcinoma genesis.

[Application of SVM and wavelet analysis in EEG classification].

We employed two methods of support vector machines (SVM) combined with two kinds of wavelet analysis to classify these EEG signals, on the basis of the different profiles, energy, and frequency characteristics of the EEG during the seizures. One method was to classify these signals using waveform characteristics of the EEG signal. The other was to classify these signals based on fluctuation index and variation coefficient of the EEG signal. We compared the classification accuracies of these two methods with the intermittent EEG and epileptic EEG. The results of the experiments showed that both the two methods for distinguishing epileptic EEG and interictal EEG can achieve an effective performance. It was also confirmed that the latter, the method based on the fluctuation index and variation coefficient, possesses a better effect of classification.

[EEG signal classification based on EMD and SVM].

The automatic detection and classification of EEG epileptic wave have great clinical significance. This paper proposes an empirical mode decomposition (EMD) and support vector machine (SVM) based classification method for non-stationary EEG. Firstly, EMD was used to decompose EEG into multiple empirical mode components. Secondly, effective features were extracted from the scales. Finally, the EEG was classified with SVM. The experiment indicated that this method could achieve good classification result with accuracy of 99 % for interictal and ictal EEGs.

Rapid DNA mapping by fluorescent single molecule detection.

DNA mapping is an important analytical tool in genomic sequencing, medical diagnostics and pathogen identification. Here we report an optical DNA mapping strategy based on direct imaging of individual DNA molecules and localization of multiple sequence motifs on the molecules. Individual genomic DNA molecules were labeled with fluorescent dyes at specific sequence motifs by the action of nicking endonuclease followed by the incorporation of dye terminators with DNA polymerase. The labeled DNA molecules were then stretched into linear form on a modified glass surface and imaged using total internal reflection fluorescence (TIRF) microscopy. By determining the positions of the fluorescent labels with respect to the DNA backbone, the distribution of the sequence motif recognized by the nicking endonuclease can be established with good accuracy, in a manner similar to reading a barcode. With this approach, we constructed a specific sequence motif map of lambda-DNA. We further demonstrated the capability of this approach to rapidly type a human adenovirus and several strains of human rhinovirus.

Per- and polyfluorinated compounds in saleswomen's urine linked to indoor dust in clothing shops.

This study aims to investigate the characteristics of typical per- and polyfluorinated compounds (PFCs) in indoor dust from clothing shops and urine sampled from saleswomen. A total of 58 indoor dust samples and 73 urine samples from saleswomen were collected from clothing shops in Shanghai, China. All samples were analyzed for PFCs using high-performance liquid chromatography tandem triple quadrupole mass spectrometry (HPLC-MS/MS). The mean PFC concentrations in indoor dust ranged from 0.42 (PFDA) to 5.04 ng g-1 (PFDoA). PFDoA and PFHxS were the most prominent PFCs, with median concentrations of 2.95 ng g-1 and 1.49 ng g-1, respectively. The median PFC concentrations in urine ranged from 10.15 (PFDS) to 666.1 ng l-1 (PFOA) and PFOA was the most abundant chemical with concentrations ranging from 207 to 907 ng l-1. A significant positive correlation was obtained between long-chain PFCs in dust and in urine (p < 0.01). Daily intake values of PFCs via dust ingestion were also calculated, and even under high-end exposure scenarios, the intake of PFOA (36.5 pg day-1) and PFOS (56.7 pg day-1) were well within the tolerable daily intake values. These results are important to both characterize PFC levels and estimate the saleswomen's exposure to PFCs from indoor dust.

A simple DNA stretching method for fluorescence imaging of single DNA molecules.

Stretching or aligning DNA molecules onto a surface by means of molecular combing techniques is one of the critical steps in single DNA molecule analysis. However, many of the current studies have focused on lambda-DNA, or other large DNA molecules. There are very few studies on stretching methodologies for DNA molecules generated via PCR (typically smaller than 20 kb). Here we describe a simple method of stretching DNA molecules up to 18 kb in size on a modified glass surface. The very low background fluorescence allows efficient detection of single fluorescent dye labels incorporated into the stretched DNA molecules.

Determination of haplotypes from single DNA molecules: a method for single-molecule barcoding.

Determining the haplotypes in a diploid individual is a major technical challenge in genetic studies of human complex traits. Here we report a method of molecular haplotyping by directly imaging multiple polymorphic sites on individual DNA molecules simultaneously. DNA fragments amplified by long-range PCR were labeled with fluorescent dyes at each polymorphic site using a modified gap-filled padlock probe ligation approach. The labeled DNA molecules were then stretched into linear form on a functionalized glass surface and imaged with multicolor total internal reflection fluorescence (TIRF) microscopy. By determining the colors and positions of the fluorescent labels with respect to the backbone at polymorphic sites, the haplotype can be inferred accurately, in a manner similar to reading a barcode, even when the DNA fragments are not fully labeled. The feasibility of this technology is demonstrated by the determination of the haplotype of a 9.3-kbp DNA fragment containing four SNPs.

A comparative study of the influence of two types of PHEMA stents on the differentiation of ASCs to myocardial cells.

In the present study, subcutaneous fat was obtained from adult women that had undergone conventional liposuction surgery. A comparative study was performed to investigate the effect of transparent and white poly­ß­hydroxyethyl methacrylate (PHEMA) stents, which have different surface and cross­sectional morphological characteristics, on the differentiation of adipose­derived stem cells (ASCs) into myocardial cells. The cell counting kit­8 assay revealed that cell growth increased at varying rates among the different treatment groups. The absorbance of the experimental transparent PHEMA treated group increased in a time­dependent manner with the duration of incubation. The highest levels of proliferation were observed in the transparent PHEMA group. In addition, the transparent PHEMA treated group exhibited the strongest cell adhesion ability, which was significantly different to that of the white PHEMA group (P<0.01 and P<0.05 for Matrigel and fibronectin assay, respectively). Comparisons between the two stent materials with the inducer control group revealed statistically significant differences in the rate of ASC differentiation (P<0.05). The level of differentiation was the greatest in the transparent PHEMA group, and was significantly different to the white PHEMA group (P<0.05) and the blank control group (P<0.01). The results suggest that the inducers 5-aza-2-deoxycytidin and laminin, and material microstructure stents effectively promote the proliferation, growth and adhesion of ASCs. However, the transparent material microstructure may be a more suitable candidate for ASC­associated injections. The present study provides further evidence that a PHEMA stent structure, comprised of a high number of matrixes and a low water content, induces a high level of ASC differentiation to myocardial cells.

[Hydrogen can alleviate post-cardiac arrest myocardium injury in rabbits].

OBJECTIVE: To investigate the effects of hydrogen (H2) on myocardium injury post-cardiac arrest (CA) in rabbits. METHODS: Sixty New Zealand rabbits were randomly divided into H2 treatment group (n = 30) and control group (n = 30) by random number table. The rabbit CA model was established by means of electrical stimulation of external membrane, both groups were mechanically ventilated. Cardiopulmonary resuscitation (CPR) was performed after 6 minutes of nonintervention, and stopped after restoration of spontaneous circulation (ROSC). Inhalation of 2% H2 gas was conferred to rabbits immediately at the end of CA modeling for 72 hours in H2 treatment group. Air was given to rabbits in control group instead. The survival rate of rabbits was analyzed. Heart rate, ventricular premature beat frequency, and the levels of blood samples cardiac troponin I (cTnI), left ventricular ejection fraction (LVEF), B-type natriuretic peptide (BNP), and blood lactic acid (Lac) were collected before CA and after ROSC in all rabbits. Rabbits were sacrificed and microstructure injury was observed by electric microscope after ROSC 72 hours. RESULTS: There were 28 animals ROSC in both groups; the survival number in H2 treatment group was higher than that in control group at 72 hours after ROSC (number: 15 vs. 7, χ2 = 4.791, P = 0.029). In the early stage of ROSC, the heart rate of two groups slowed down, the number of premature ventricular increased, and then gradually recovered; the heart rate in H2 treatment group was returning to normal more quickly than that in control group at 48 hours after ROSC (bpm: 319±63 vs. 362±40, P < 0.05); the ventricular premature beat frequency was lower than that in control group at 72 hours after ROSC (times per minutes: 9.1±4.3 vs. 15.0±8.0, P < 0.05). The animals of two groups had different degrees of myocardial damage and cardiac insufficiency after ROSC, and restored with the extension of time. Compared with control group, the level of BNP in H2 treatment group was significant decreased at 24 hours after ROSC (ng/L: 385±98 vs. 488±174, P < 0.05), the levels of cTnI and Lac were significant decreased at 48 hours after ROSC [cTnI (µg/L: 1.83±0.68 vs. 2.83±0.98, Lac (mmol/L): 5.5±1.6 vs. 7.9±2.6, both P < 0.01], the LVEF was slightly higher than that at 72 hours after ROSC (0.690±0.040 vs. 0.650±0.041, P = 0.051). Compared with control group, less damage to myocardial ultra structure was found in H2 treatment group at 72 hours after ROSC. CONCLUSIONS: Inhalation of H2 alleviates cardiac dysfunction and myocardial injury after CPR.

Effect of high porosity on biodegradation of poly (4-hydroxybutyrate) in vivo.

Poly-4-hydroxybutyrate, P(4HB), is a biosynthetic thermoplastic polymer that has been studied as a bio-absorbable medical material. In order to explore the in vivo biodegradation behaviour of porous P(4HB) membranes with specified apertures (89-150 µm), membranes with different porosities were implanted subcutaneously into the backs of 27 eight-week-old Sprague Dawley® rats. The implanted specimens were examined with Masson and hematoxylin and eosin staining. Masson staining indicated that the P(4HB) membranes were encased in fibrous cysts and that more collagen fibers were present within the sections of the hyper-porosity group. Hematoxylin and eosin staining showed that the residual area of the P(4HB) membranes in the hyper-porosity group decreased sharply compared to the hypo-porosity group, which implied that the P(4HB) membranes with higher porosity degraded faster than those with lower porosity. A slow degradation phase persisted for approximately 14 weeks during the degradation process. After the 16th week, the P(4HB) scaffolds fell into a fast degradation phase. The residual areas of the hyper-porosity P(4HB) membranes at the 32nd week were reduced by 39.76% compared with the second week after implantation. We concluded that P(4HB) membranes manifest a special biodegradation behavior in vivo and that the increased porosity of these membranes is an important factor favoring their biodegradation rates.

In vitro hemocompatibility evaluation of poly (4-hydroxybutyrate) scaffold.

The biosynthetic thermoplastic poly-4-hydroxybutyrate (P4HB) possesses favorable tensile strength and elongation performance and has been studied as a new implantable polymer material for medical uses. However, its hemocompatibility has not been tested to confirm its applicability to tissue engineering. In this study, a series of experiments was performed that included erythrocyte hemolysis tests, dynamic blood coagulation tests, platelet adhesion tests, effects on blood coagulation, Wright staining, and adsorption of erythrocytes, leukocytes, platelets, and plasma proteins. The results were compared with control tests on polyvinyl chloride (PVC), a biomaterial in current use, to evaluate the relative in vitro hemocompatibility of P4HB. The degree of hemolysis in the presence of P4HB was 1.9 ± 0.2%. The absorbance-time curve for blood clotting declined slowly and smoothly. There were no differences in the test values of Factor XII, activated partial thromboplastin time (APTT), or fibrin degradation products (FDPs) among whole blood samples exposed to P4HB or PVC and the blank control groups (P > .05). Adsorption of platelets and globulin was similar in samples exposed to P4HB and PVC (P > .05), but the adsorption of erythrocytes, leukocytes, and albumin to P4HB was higher (P < .05). In conclusion, P4HB compares favorably with PVC in terms of blood compatibility, except for a higher affinity for erythrocytes and leukocytes. The findings indicate that P4HB, an alternate scaffolding material with advantageous properties, is generally acceptable for bioengineering use.