Genome-wide and differential proteomic analysis of hepatitis B virus and aflatoxin B1 related hepatocellular carcinoma in Guangxi, China.

Both hepatitis B virus (HBV) and aflatoxin B1 (AFB1) exposure can cause liver damage as well as increase the probability of hepatocellular carcinoma (HCC). To investigate the underlying genetic changes that may influence development of HCC associated with HBV infection and AFB1 exposure, HCC patients were subdivided into 4 groups depending upon HBV and AFB1 exposure status: (HBV(+)/AFB1(+), HBV(+)/AFB1(-), HBV(-)/AFB1(+), HBV(-)/AFB1(-)). Genetic abnormalities and protein expression profiles were analyzed by array-based comparative genomic hybridization and isobaric tagging for quantitation. A total of 573 chromosomal aberrations (CNAs) including 184 increased and 389 decreased were detected in our study population. Twenty-five recurrently altered regions (RARs; chromosomal alterations observed in ≥10 patients) in chromosomes were identified. Loss of 4q13.3-q35.2, 13q12.1-q21.2 and gain of 7q11.2-q35 were observed with a higher frequency in the HBV(+)/AFB1(+), HBV(+)/AFB1(-) and HBV(-)/AFB1(+) groups compared to the HBV(-)/AFB(-) group. Loss of 8p12-p23.2 was associated with high TNM stage tumors (P = 0.038) and was an unfavorable prognostic factor for tumor-free survival (P =0.045). A total of 133 differentially expressed proteins were identified in iTRAQ proteomics analysis, 69 (51.8%) of which mapped within identified RARs. The most common biological processes affected by HBV and AFB1 status in HCC tumorigenesis were detoxification and drug metabolism pathways, antigen processing and anti-apoptosis pathways. Expression of AKR1B10 was increased significantly in the HBV(+)/AFB1(+) and HBV(-)/AFB1(+) groups. A significant correlation between the expression of AKR1B10 mRNA and protein levels as well as AKR1B10 copy number was observered, which suggest that AKR1B10 may play a role in AFB1-related hepatocarcinogenesis. In summary, a number of genetic and gene expression alterations were found to be associated with HBV and AFB1- related HCC. The possible synergistic effects of HBV and AFB1 in hepatocarcinogenesis warrant further investigations.

[Association between myocardial calpain activation and apoptosis in lipopolysaccharide-induced septic mouse model].

OBJECTIVE: in septic mice, myocardial calpain was activated and induced caspase-3 activation, the association between calpain activation and apoptosis was explored in this experiment. METHODS: in in vivo model, adult C57 mice were injected with lipopolysaccharide (LPS, 4 mg/kg, i.p.) to induce sepsis. Myocardial calpain and caspase-3 activities, protein levels of calpain-1, calpain-2, calpastatin, Bcl-2 and Bid were detected by Western blot analysis and myocardial apoptosis was detected by TUNEL, myocardiac function was evaluated by Langendorff system. In in vitro model, adult rat cardiomyocytes were incubated with LPS (1 microg/ml) or co-incubated with calpain inhibitor-III (10 micromol/L), calpain activity, caspase-3 activity, protein levels of Bcl-2 and Bid, and cardiomyocyte apoptosis were detected. RESULTS: in septic mice, myocardial calpain and caspase-3 activity were increased up to 2.7- and 1.8-folds, respectively. Both calpain inhibitor-III and PD150606 significantly attenuated the increase of caspase-3 activity. Myocardial protein levels of calpain-1, calpain-2, calpastatin, Bcl-2 and Bid were similar between control and septic mice, and no cleavage of both Bcl-2 and Bid was found in septic mice. Calpain inhibitor-III significantly improved myocardial function in septic mice. In in vitro model, calpain and caspase-3 activities were increased after 4 h LPS treatment, co-treatment with calpain inhibitor-III prevented caspase-3 activity increase, protein Bcl-2 and Bid were similar between normal cardiomyocytes and LPS-treated cardiomyocytes. Cardiomyocyte apoptosis was similar in in vivo and in vitro septic models. CONCLUSION: myocardial calpain activity is increased in LPS induced septic mice, subsequent caspase-3 activation may contribute to myocardial dysfunction in septic mice without aggravating myocardial apoptosis and Bcl-2 and Bid are not involved on calpain induced caspase-3 activation in our model.

[Cardiomyocyte apoptosis and death receptor pathway in a rat model of coronary microembolization].

OBJECTIVE: To investigate the dynamic changes of cardiomyocyte apoptosis and the role of death receptor apoptotic pathway in a rat model of coronary microembolization (CME). METHODS: Adult rats were randomized to coronary microembolization (CME group, n = 63) or sham-operated group (S group, n = 55). CME model was established by aortic injection of 0.1 ml microspheres (42 microm, 3 x 10(4)/ml) into the left ventricle when the ascending aorta was temporarily clamped.S group received 0.1 ml saline injection and survived rats were randomly examined at 0, 3, 6, 12 and 24 hour post CME (n = 10 each). Heart function was evaluated by echocardiography. Myocardium sample was stained with hematoxylin-eosin and hematoxylin-basic fuchsin-picric acid to detect infarct areas. Cardiomyocyte apoptosis was detected with TUNEL staining. The expression of caspase-3 and caspase-8 was measured by Western blot analysis. RESULTS: Compared with S group, the left ventricular ejection fraction was significantly decreased and left ventricular end-diastolic diameter was significantly increased in CME group (all P < 0.05) except 0 hour CME group. The infarct sizes were similar in 3 hour, 6 hour, 12 hour, and 24 hour CME groups (P > 0.05). The apoptosis index (AI) in CME group were significantly higher at each time point compared to S group (P < 0.05) except 0 hour CME group and peaked at 6 hours. Apoptotic cardiomyocytes were found mainly in the myocardial microinfarcted area and border zones. The relative expression of caspase-3 and caspase-8 in CME group were both significantly increased at 3 hours and peaked at 6 hour post CME (P < 0.05). CONCLUSION: Cardiomyocytes apoptosis was significantly increased after coronary microembolization via activating death receptor apoptotic pathway in this coronary microembolization model.

Enhanced prothrombin formation and platelet activation in Chinese patients after transcatheter closure of atrial septal defect.

BACKGROUND: The objective of this study was to investigate changes in coagulation activation and platelet activation after transcatheter closure of atrial septal defect (ASD) by determining the levels of specific markers over time to provide insight into preventing postprocedural embolism. HYPOTHESIS: We hypothesis that the activation status of coagulation and the platelet would be changed after the closure of ASD. METHODS: Forty consecutive patients who underwent transcatheter closure of ASD with the Lifetech ASD occluder (Lifetech Scientific, Shenzhen, China) were included in this prospective study. The serum level of prothrombin fragment 1 + 2 (F1 + 2) and expressions of P-selectin (CD62P) and platelet glycoprotein IIb/IIIa receptor (CD41a) on the surface of platelets were evaluated at baseline and at 1 day, 1 month, and 3 months after the closure. RESULTS: The median F1 + 2 level was 0.96 nmol/L. This increased to a maximal value of 1.43 nmol/L at 1 day after closure, but gradually returned to the baseline level at 1 month after closure and remained there at 3 months after closure (medians were 0.98 nmol/L and 1.08 nmol/L, respectively). Platelet surface expression of CD62P and CD41a decreased at 1 day, 1 month, and 3 months after closure. For CD62P, average expressions were 8.21% +/- 2.11%, 6.28% +/- 1.72%, 5.29% +/- 1.52%, and 4.41% +/- 1.11%, respectively, for baseline and 1 day, 1 month, and 3 months after closure. For CD41a, average expressions were 79.37% +/- 14.14%, 71.98% +/- 13.77, 56.69% +/- 13.05%, and 54.88% +/- 11.62%, respectively. CONCLUSIONS: Transcatheter closure of ASD with the Lifetech ASD occluder was associated with significantly increased coagulation activation and decreased platelet activation. No evidence supporting the use of aspirin to prevent thrombus formation after closure was found.

[Myocardial inflammation and injury induced by coronary microembolization in rats: role of ERK1/2 signaling pathway].

OBJECTIVE: To determine the role of extracellular signal-regulated kinases1/2 (ERK1/2) signaling pathway in regulating myocardial inflammation and cardiac function in a rat model of coronary microembolization (CME). METHODS: The Sprague-Dawley rats were randomly divided into three groups: sham-operated group (n = 15), coronary microembolization group (n = 15) and PD98059 group (n = 15). CME model was established by injection of 42 microm microspheres 0.1 ml (3 x 10(4)/ml, 3000)into left ventricle while occluding the ascending aorta. At 30 minutes pre-operation, rats of PD98059 group were injected with PD98059 IV, a specific ERK1/2 inhibitor. Western blot and immunochemical analysis were used to determine the activation and distribution of ERK1/2. Echocardiography was employed to evaluate cardiac functions. The hematoxylin-eosin staining was used to assay myocardial inflammation. Expression of TNF-alpha and MIF mRNA was determined by RT-PCR analysis and activity of NF-kappaB assessed by electrophoretic mobility shift assay. RESULTS: In comparison with sham-operated group, CME increased phosphorylation of ERK1/2 (0.92 +/- 0.10 vs 0.61 +/- 0.04), local myocardial inflammatory cells (455 +/- 16 vs 47 +/- 7), expression of TNF-alpha mRNA (0.94 +/- 0.04 vs 0.60 +/- 0.09) and MIF mRNA(1.30 +/- 0.44 vs 0.63 +/- 0.25) and activity of NF-kappaB (541 +/- 25 vs 311 +/- 65) in myocardium(all P < 0.05). All of these dramatically induced cardiac dysfunction [LVEF (73 +/- 3)% vs (83 +/- 4)%, P < 0.05]. To compare with CME group, treatment of specific ERK1/2 inhibitor PD98059 blocked the activation of ERK1/2 (0.48 +/- 0.11 vs 0.92 +/- 0.10, P < 0.05), decreased inflammatory cells (401 +/- 12 vs 455 +/- 16, P < 0.05), decreased expression of TNF-alpha mRNA (0.42 +/- 0.06 vs 0.94 +/- 0.04, P < 0.05) and suppressed activity of NF-kappaB (105 +/- 14 vs 541 +/- 25, P < 0.05). Most importantly, PD98059 treatment ameliorated cardiac functions dramatically [LVEF (76 +/- 4)% vs (73 +/- 3)%, P < 0.05]. However there was no significant change in the expression of MIF mRNA (1.17 +/- 0.37 vs 1.30 +/- 0.44, P > 0.05). CONCLUSION: The present study demonstrates a novel role of ERK1/2 signaling pathway in promoting myocardial inflammation in CME. And ERK1/2 may be a novel drug target for CME therapy.

GATA4 mutations in Chinese patients with congenital cardiac septal defects.

The object of the study was to elucidate the mutations of the GATA4 gene in Han ancestry patients with congenital cardiac septal defects. Fifty Han ancestry patients with sporadic and familial cardiac septal defects and 200 normal subjects of the same ethnical background were studied. A total of six exons and the intron-exon boundaries of GATA4 were amplified by polymerase chain reaction (PCR). The PCR products were purified and directly sequenced with an ABI PRISM 3730 Automatic DNA sequencer. Two novel heterozygous mutations were discovered in the GATA4 gene in five children with cardiac septal defects (10%, 5/50), His28Tyr in exon 2 and His436Tyr in exon 7, respectively, which were neither found in the control population nor reported in the SNP database at the website http://www.ncbi.nlm.nih.gov/SNP. In addition, we did not identify any mutations in GATA4 in three familial atrial septal defects and two familial ventricular septal defects. Our finding suggests that the mutations in the transcription factor GATA4 might be related to congenital cardiac septal defects in Han ancestry patients.

[Association between GATA-4 mutations and congenital cardiac septal defects in Han Chinese patients].

OBJECTIVE: To elucidate the association between GATA-4 gene mutations and congenital cardiac septal defects in Han Chinese patients. METHODS: Fifty Han Chinese patients with congenital cardiac septal defects and 100 normal subjects with the same ethnical background were studied. Total six exons and the intron-exon boundaries of GATA-4 were amplified by the polymerase chain reaction. The polymerase chain reaction products were purified and directly sequenced with automatic sequencer. RESULTS: Two novel heterozygous mutations were discovered in the GATA-4 gene of patients with congenital cardiac septal defects, His28Tyr in exon 2 and His436Tyr in exon 7 respectively, which were absent in the control population and not reported in the SNP database (http://www.ncbi.nlm.nih.gov/SNP). CONCLUSION: Our finding suggests that the mutations in the transcription factor GATA-4 may be related to congenital cardiac septal defects in Han Chinese patients.

[Preliminary functional analysis of a novel mutation in GATA-4 gene in Chinese patients with congenital cardiac septal defects].

OBJECTIVE: To perform the functional analysis of a novel H436Y mutation of GATA-4 gene identified in Han Chinese patients with congenital cardiac septal defects. METHODS: Using bioinformatics to predict if the H436Y mutation in the GATA-4 gene affects its protein function. H436Y mutation in the GATA-4 gene was generated by Quick Change Lightning site-directed mutagenesis kit and verified by DNA sequencing. GATA-4-wt or GATA-4-mut DNA was cotransfected into Hela cells with DNA for the luciferase reporter gene atrial natriuretic factor (ANF), and luciferase activity was measured by an LKB luminometer 48 h after transient transfection. RESULTS: Alignment of the GATA-4 amino acid sequence indicated that the histidine residue at position 436 was conserved, and H436Y mutation in the GATA-4 gene is expected to affect its protein function. The H436Y mutation significantly reduced the transcriptional activation of downstream reporter ANF when compared to wild-type GATA-4 (P<0.01). CONCLUSION: The mutation c.1306C-->T of the GATA-4 gene impaired the activation of the downstream target, suggesting that the H436Y mutation in the C-terminal region of the GATA-4 gene might prevent its biological function.

[Effects of Astragalus injection in reversing left ventricular hypertrophy induced by renal hypertension in rats].

OBJECTIVE: To explore whether the Astragalus injection (AI) has effect for reversing left ventricular hypertrophy and myocardial fibrosis induced by renal vascular hypertension in rats. METHODS: Thirty male SD rats were randomized equally into three groups: the AI group, the control group and the sham-operated group. All rats, except those in the sham-operated group, were established into the hypertension models by two kidney one clip (2K1C) operation. Blood pressure was measured before operation and every 4 weeks after operation. AI intervention was given to rats in the AI group starting from the 4th week of experiment at dose of 8 g/kg by peritoneal injecting once a day for 8 weeks, while for rats in the other 2 groups, equal volume of normal saline was given instead. All rats were sacrificed 12 weeks after operation by cervical breaking. And indexes including left ventricular mass index (LVMI), left ventricular wall thickness (LVWT), inter-ventricular septal thickness (IVST), left ventricular diameter (LVD), cardiomyocytes diameter (CCD), collagen volume fraction (CVF), and peri-vascular volume collagen area (PVCA) in rats were measured. RESULTS: Blood pressure was not different in the three groups before operation (P>0.05), whereas it rose in the control group and the AI group 4, 8 and 12 weeks after operation correspondingly, showing no difference between the two groups, but significantly higher than that in the sham-operated group (P<0.05). The related indexes in the sham-operated group, control group and AI group were: LVMI, 2.71 +/- 0.24, 3.42 +/- 0.26, 3.13 +/- 0.23, respectively; LVWT (mm), 2.25 +/- 0.42, 4.26 +/- 0.48, 3.28 +/- 0.36; IVST (mm), 2.13 +/- 0.38, 3.98 +/- 0.32, 3.02 +/- 0.28; and LVD (mm), 3.76 +/- 0.29, 2.18 +/- 0.27, 2.82 +/- 0.20 respectively. Comparisons showed that LVMI, LVWT and IVST were significantly higher, but LVD was significantly lower in the control group than those in the sham-operated group (P<0.05); LVMI, LVWT and IVST were significantly lower but LVD was significantly higher in the AI group than those in the control group (P<0.05). CCD, CVF and PVCA in the three groups (in the fore-mentioned order) were: CCD (microm), 14.54 +/- 2.25, 19.56 +/- 2.53, 16.58 +/- 2.46; CVF(%), 3.83 +/- 1.40, 11.21 +/- 2.96, 7.83 +/- 1.67; PVCA (%), 15.71 +/- 3.85, 30.58 +/- 6.25, 21.76 +/- 4.36, respectively. These indexes showed that CCD, CVF, PVCA in the control group were significantly higher than those in the sham-operated group (P<0.05); and those were significantly lower in the AI group than in the control group (P<0.05). CONCLUSION: AI intervention can reverse the left ventricular hypertrophy and myocardial fibrosis induced by renal vascular hypertension in rats.

Hepatitis B virus infection contributes to oxidative stress in a population exposed to aflatoxin B1 and high-risk for hepatocellular carcinoma.

Biomarkers of hepatitis B virus (HBV) infection, aflatoxin B1 (AFB1) exposure and oxidative stress were detected in 71 hepatocellular carcinoma (HCC) patients and 694 controls from southern China. Plasma level of AFB1-albumin-adducts (AAA) and protein carbonyl content (PCC) were significantly higher in the 71 HCC cases than in any age/gender matched HBV sero-status groups (p<0.001). HCC patients positive for the p53-249 G-T mutation had a marginally higher level of PCC than those negative for the mutation (p=0.077). HBV infection had a prominent influence on the association between AFB1 exposure and oxidative stress biomarkers in the controls. Our study indicates a significant contribution from HBV infection to oxidative stress in a population with AFB1 exposure which might substantially increase risk for HCC in this region.

Combination of cardiac pacing and epinephrine does not always improve outcome of cardiopulmonary resuscitation.

We hypothesized that the combination of cardiac pacing and epinephrine would yield a better efficacy for cardiopulmonary resuscitation (CPR) and the combination of 2 therapies at different opportunity would achieve the same results of CPR. Cardiac arrest was induced by clamping the tracheal tubes in 60 Sprague-Dawley rats. At 10 minutes of asphyxia, the animals were prospectively randomized into 5 groups (n = 12/group), and received saline (Sal-gro, 1 mL, intravenous [i.v.]), epinephrine (Epi-gro, 0.4 mg/kg, i.v.), pacing (Pac-gro, transesophageal cardiac pacing combined with saline 1 mL, i.v.), pacing + epinephrine group 1 (PE-gro1, transesophageal cardiac pacing combined with epinephrine 0.4 mg/kg, i.v.), or pacing + epinephrine group 2 (PE-gro2, transesophageal cardiac pacing combined with epinephrine 0.4 mg/kg, i.v., 4 minutes after the transesophageal cardiac pacing initiating and failing to resuscitate the animals), followed by initiation of CPR. Restoration of spontaneous circulation in Sal-gro was lower than in Epi-gro, Pac-gro, PE-gro1, and PE-gro2 (16.67% vs 66.67%, 66.67%, 100%, and 100%; P < .05 or P < .001, respectively). The proportions of withdrawing ventilator and 2-hour survival proportions in Pac-gro and PE-gro2 were higher than in Epi-gro and PE-gro1 (8/8, 10/12 vs 1/8, 2/12, respectively, P < .01, and 7/8, 8/12 vs 1/8, 2/12, respectively, P < .05 or P < .01). Mean survival time in Pac-gro and PE-gro2 were longer than in Epi-gro and PE-gro1 (P < .05 or P < .01). Therefore, the combination of 2 therapies does not always improve outcome of CPR. It is obvious that the combination of transesophageal cardiac pacing with delayed administration of epinephrine yields a better outcome compared to the combination of 2 therapies at the same time during CPR in a rat asphyxia cardiac arrest model.

Evaluation of oxidative stress in a group of adolescents exposed to a high level of aflatoxin B1--a multi-center and multi-biomarker study.

The association between aflatoxin B1 (AFB1) exposure and oxidative stress was extensively examined in 84 adolescents from an area at high risk for hepatocellular carcinoma in China. Plasma level of aflatoxin B1-albumin adducts (AAAs) was associated with AFB1 excretion in urine (r = 0.394, P < 0.001). Urinary AFB1 was also associated with both the urinary excretion of 8-hydroxydeoxyguanosine (8-OHdG) (r > or = 0.479, P < 0.001) and 8-OHdG and hOGG1 levels in peripheral leukocytes (r > or = 0.308, P < or = 0.005). Similarly, AAA was significantly associated with both the urinary excretion of 8-OHdG (r > or = 0.259, P < or = 0.018) and the 8-OHdG and hOGG1 levels in peripheral leukocytes (r > or = 0.313, P < or = 0.004). In addition, urinary 8-OHdG was correlated with both the level of DNA 8-OHdG (r > or = 0.24, P < or = 0.05) and the expression of hOGG1 in peripheral leukocytes (r > or = 0.429, P < 0.001). Protein carbonyl content (PCC) level was significantly associated with not only the level of DNA 8-OHdG (r > or = 0.366, P < 0.001) and the urinary 8-OHdG (r > or = 0.258, P < or = 0.018) but also the expression of hOGG1 in peripheral leukocytes (r = 0.485, P < 0.001). A significant but weak association was found between high-performance liquid chromatograph-electrochemical detection (HPLC-ECD) and enzyme-linked immunosorbent assay (ELISA) for urinary 8-OHdG (r = 0.334, P = 0.002) and between HPLC-ECD and flow cytometry assays for 8-OHdG in leucocytes (r = 0.395, P < 0.001). Significant associations were observed between AAA and PCC and liver function indices (alanine aminotransferase and aspartate aminotransferase). These findings suggest significant contribution from AFB1 exposure to oxidative stress and subsequent repair among adolescents that may impose substantial risk for hepatocarcinogenesis in adulthood in this region.

[Effect of mesenchymal stem cells transplantation on heart function after acute myocardial infarction].

OBJECTIVE: To investigate whether mesenchymal stem cells (MSCs) transplantation after acute myocardial infarction (AMI) can improve heart function and decrease infarct size in rabbits and their correlation. METHODS: Twenty-four rabbits were randomly divided into AMI group and MSCs group, each n=12. Exogenous MSCs labeled with bromodeoxyuridine (BrdU) were injected into the border and central area of the ischemic myocardium. Heart function was assessed with echocardiography before transplantation of MSCs and in 6th week after the transplantation. Surviving MSCs in infarcted myocardium were identified by immunohistochemistry. Infarct size was measured histologically. Correlation of heart function and infarct size were analysed. RESULTS: Immunohistochemical stain revealed that BrdU-positive cells were seen in the infarcted myocardium in MSCs group but not in AMI group. Transplantation of MSCs was associated with a significant diminution of left ventricular end-diastolic dimension (LVEDD), and left ventricular end-systolic dimension (LVESD, both P<0.05), and left ventricular ejection fraction (LVEF) and fractional shortening (DeltaFS%)increased (both P<0.05) as compared with AMI group. Infarct size as measured histologically was significant smaller in MSCs group than AMI group (P<0.05). There were negative correlations between LVEF and infarct size in two groups (both P<0.01). CONCLUSION: Exogenous MSCs transplantation can improve heart function by decreasing infarct size and therefore it might be beneficial in the treatment of AMI.

A simpler cardiac arrest model in rats.

Two disadvantages of electrical induction of cardiac arrest used currently are that it is a technically complicated procedure and the consequent thermal injury, which prompts us to search for a simpler method with less adverse effect to induce ventricular fibrillation (VF) in rats. Different potential (18, 24, 30, and 36 V) of alternating current (AC) were administered to elicit VF in 15 rats via pacing electrode placed in esophagus. Four minutes after onset of VF, conventional cardiopulmonary resuscitation (CPR) was initiated. Restoration of spontaneous circulation was defined as the return of supraventricular rhythm with a mean aortic pressure of 20 mm Hg or greater for a minimum of 5 minute. Ventricular fibrillation was achieved by short interval of AC stimulation in all of the rats. After the termination of prolonged AC stimulation, electrocardiogram indicated VF occurred in 6 of 15 rats, asystole in 3 of 15 rats and pulseless electrical activity in 6 of 15 rats. Before CPR, however, electrocardiogram indicated that only 2 of 15 and 4 of 15 animals remained in VF and pulseless electrical activity, respectively, whereas 9 of 15 animals presented as asystole. After CPR, 11 of 15 animals were resuscitated. Necropsy showed that there was no gross evidence of thermal injury on the surface layer of the heart. Therefore, development of a rat cardiac arrest model by transesophageal AC stimulation is simpler and less adverse effect, which may have practical significance for facilitating experimental investigation on cardiac arrest and CPR.

A simpler cardiac arrest model in the mouse.

OBJECTIVE: Delivering alternating currency (AC) to right ventricular endocardium to induce ventricular fibrillation (VF) in mice is complicated. We tried to validate whether transoesophageal AC stimulation could induce VF and how long AC stimulation had to be sustained to prevent the spontaneous cardioversion of VF in mice. METHODS: A pacing electrode was inserted orally into the oesophagus and AC was delivered to esophagus through the pacing electrode to stimulate the heart and induce VF in 15 mice. The incidence of VF and time of AC stimulation were recorded 4min after onset of VF cardiopulmonary resuscitation (CPR) was started. RESULTS: VF was induced by short AC stimulation in all 15 mice. With the prolongation of AC stimulation, the incidences of spontaneous cardioversion of VF decreased whereas the incidence of pulseless electrical activity (PEA) increased accordingly. Following the termination of prolonged AC stimulation, VF occurred only in 1 of 15 mice, but PEA in 14 of 15 mice. Before CPR 1 of 15 and 12 of 15 animals remained in VF and in PEA, respectively, while 2 of 15 animals developed into asystole. After CPR, 11 of 15 animals were successfully resuscitated. CONCLUSION: VF can be induced by a short period of transoesophageal AC stimulation in mice. However, prolonged AC stimulation is prone to induce PEA other than VF. Nonetheless, the development of a mouse CA model in this manner is simpler and easier, which may have practical significance for facilitating experimental investigation on CA and CPR.

Epinephrine, but not vasopressin, improves survival rates in an adult rabbit model of asphyxia cardiac arrest.

Although vasopressin has been reported to be more effective than epinephrine for cardiopulmonary resuscitation in ventricular fibrillation animal models, its efficacy in asphyxia model remains controversy. The purpose of this study was to investigate the effectiveness of vasopressin vs epinephrine on restoration of spontaneous circulation (ROSC) in a rabbit model of asphyxia cardiac arrest. Cardiac arrest was induced by clamping endotracheal tube. After 5 minutes of basic life-support cardiopulmonary resuscitation, animals who had no ROSC were randomly assigned to receive either epinephrine alone (epinephrine group; 200 microg/kg) or vasopressin alone (vasopressin group; 0.8 U/kg). The coronary perfusion pressure (CPP) was calculated as the difference between the minimal diastolic aortic and simultaneously recorded right atrial pressure. Restoration of spontaneous circulation was defined as an unassisted pulse with a systolic arterial pressure of 60 mm Hg or higher for 5 minutes or longer. We induced arrest in 62 rabbits, 15 of whom had ROSC before drug administration and were excluded from analysis. The remaining 47 rabbits were randomized to epinephrine group (n = 24) and vasopressin group (n = 23). Before and after drug administration, CPP in epinephrine group increased significantly (from -4 +/- 4 to 36 +/- 9 mm Hg at peak value, P = .000), whereas CPP in vasopressin group increased only slightly (from 9 +/- 5 to 18 +/- 6 mm Hg at peak value, P = .20). After drug administration, 13 of 24 epinephrine rabbit had ROSC, and only 2 of 23 vasopressin rabbit had ROSC (P < .01). Consequently, we conclude that epinephrine, but not vasopressin, increases survival rates in this adult rabbit asphyxia model.

Ventricular fibrillation induced by transoesophageal cardiac pacing: a new model of cardiac arrest in rats.

OBJECTIVE: To investigate whether transoesophageal cardiac pacing can induce ventricular fibrillation (VF) and how long the cardiac pacing has to be sustained to prevent the reversion of the VF induced. METHODS: A pacing electrode was inserted orally into the oesophagus and high-frequency ventricular pacing was performed so as to elicit VF in 25 Sprague-Dawley rats. Incidences of VF and time of cardiac pacing were observed and recorded. Four minutes after onset of VF cardiopulmonary resuscitation (CPR) was initiated. RESULTS: A short interval of high-frequency ventricular pacing caused an immediate drop of blood pressure, loss of pulse and increase of right atrial pressure in the same time frame. When the cardiac pacing was terminated, VF was elicited at least once or more than once in all of the 25 rats. However, the VF elicited by the burst stimulation could be defibrillated spontaneously. With the prolongation (120-180 s) of cardiac pacing, the incidence of defibrillation of VF decreased from 100 to 0%. VF persisted in 19 of 25 animals, developed into asystole in 5 of 25 animals and converted into pulseless electrical activity in 1 of 25 animals prior to CPR. Following CPR 22 of 25 animals were resuscitated. CONCLUSIONS: Transoesophageal cardiac pacing can induce VF in rats. However, the cardiac pacing is required for at least 120-180 s to ensure that VF does not spontaneously convert. We can use the technique to establish a new and simpler rat cardiac arrest (CA) model, which may facilitate experimental investigation on CPR.

Is correction for protein concentration appropriate for protein adduct dosimetry? Hypothesis and clues from an aflatoxin B1-exposed population.

Protein adducts are useful biomarkers for assessing exposure, metabolism and risk of carcinogens. Aflatoxin B1-albumin adducts (AAA) and protein carbonyl content (PCC) have long been used for assessing aflatoxin exposure and oxidative stress to proteins, and the quantitative data are almost exclusively expressed per mg protein. Given the large variation in protein concentrations in plasma among populations, this may not be the most appropriate method. The objective was to test the hypothesis that AAA and PCC should be expressed per mL plasma in population studies. AAA and PCC were analyzed among 402 subjects from three regions of China with a gradient in hepatocellular carcinoma (HCC) mortality ranging from 21 to 97 per 100,000. When biomarker values were expressed per mL plasma, the AAA level was significantly associated with plasma PCC (r = 0.262, P < 0.001), and adjusted levels of AAA and PCC paralleled HCC mortalities in the three regions, suggesting a role for aflatoxin-related oxidative stress in hepatocarcinogenesis in this population. In addition, there were statistically significant associations between both protein biomarkers, expressed per mL plasma, and the levels of alanine aminotransferase and aspartate aminotransferase in hepatitis B virus-infected subjects, suggesting roles for aflatoxin exposure, oxidative stress and hepatitis B virus infection in the development of HCC. The present data suggest that interindividual variation in plasma protein concentration may influence the dosimetry and relevant interpretation of protein biomarkers.

A comparison of transoesophageal cardiac pacing and epinephrine for cardiopulmonary resuscitation.

The use of cardiac pacing to deal with bradycardia is well established. There is debate as to the benefits during cardiopulmonary resuscitation (CPR). This study was performed to compare the effects of transoesophageal cardiac pacing and high-dose epinephrine on the benefits of cardiopulmonary resuscitation after asphyxial cardiac arrest in rats. Thirty Sprague-Dawley rats of both sexes were randomly selected to a saline group (Sal-gro, treated with normal saline 1 mL IV, n = 10), an epinephrine group (Epi-gro, treated with epinephrine 0.4 mg/kg IV, n = 10), or a pacing group (Pac-gro, treated with normal saline 1 mL IV combined with transoesophageal cardiac pacing, n = 10) in a blinded fashion during resuscitation after 10 minutes of asphyxial cardiac arrest. Manual chest compression was in all cases performed using the same methodology by the same personnel who was blinded to hemodynamic monitor tracings. The rate of restoration of spontaneous circulation was 1 (10%), 7 (70%), and 8 (80%) of 10 in Sal-gro, Epi-gro, and Pac-gro, respectively. The rate of ventilator withdrawal within 60 minutes after resuscitation in Pac-gro was higher than that of Epi-gro (8/8 vs 1/7, respectively; P = .001); the survival rate after 2 hours in Pac-gro was significantly higher than that in Epi-gro (7/8 vs 1/7, respectively; P = .01). The data demonstrate that both epinephrine and transoesophageal cardiac pacing are effective within 10 minutes of asphyxia in rats. It is worth noting that transoesophageal cardiac pacing produced a better outcome with respiration and longer survival time compared with epinephrine after restoration of spontaneous circulation.