Predictive Value of Exercise Blood Pressure Changes for Orthostatic Hypotension in Patients With Parkinson's Disease.

BACKGROUND AND PURPOSE: Orthostatic hypotension (OH) is common in patients with Parkinson's disease (PD). Early recognition OH is required with sensitive assessments. The purpose of this study was to determine whether blood pressure (BP) changes during exercise can predict the occurrence of OH in PD. METHODS: This prospective cohort study included 80 consecutive patients with PD. All patients agreed to participate in a baseline evaluation and cardiopulmonary exercise test (CPET). According to the initial active standing test (AST), those without OH (PD-nonOH) at baseline had their AST results followed up for 6 months. The main outcome was defined as whether patients without OH at baseline would develop OH after 6 months. Logistic regression analysis was applied to identify the relevant variables. A nomogram was constructed based on clinical features and identified variables. The concordance index (C-index) and area under the receiver operating characteristic curve (AUC) were used to evaluate the accuracy and predictive ability of the nomogram, respectively. RESULTS: CPET results indicated that peak load, peak heart rate, heart rate recovery at 1 min, and systolic BP change (ΔSBP) were lower in those with OH than in the PD-nonOH group (p<0.05) at baseline. Logistic regression analysis indicated that peak load and ΔSBP during CPET had significant effects on OH (p<0.05). Age, sex, peak load, and ΔSBP were used to construct the nomogram model (C-index=0.761). The prediction model had an AUC of 0.782 (95% confidence interval=0.649-0.889) and a specificity and sensitivity of 70.0% and 81.8%, respectively. CONCLUSIONS: This study has identified predictive factors for OH development in patients with PD. CPET could be used as a complementary examination to identify patients at a high risk of OH.

[Cardiopulmonary exercise testing (CPET)to evaluate the efficacy after intensive control of personalized precise exercise training for cardiovascular and cerebrovascular chronic diseases].

Objective: To study the symptom-restricted extreme cardiopulmonary exercise testing (CPET) to evaluate the improvement of the overall function of patients with long-term chronic diseases after intensive control of personalized precise exercise training for 3 months. Methods: We selected 20 patients with chronic cardiovascular and cerebrovascular metabolic diseases who were intensively controlled by our team from 2014 to 2016. After signing the informed consent form, based on the results of CPET and continuous functional tests, we formulated the overall management plan with individualized moderate exercise intensity as the core. After 3 months, CPET was performed. The changes of CPET indicators before and after intensive control in each patient were analyzed individually. Then the difference value and percentage difference value were calculated. Results: In this study, 20 patients (18 males and 2 females) with chronic cardiovascular and cerebrovascular metabolic diseases, aged (55.75±10.80, 26~73) years, height (172.20±8.63, 153~190) cm, weight (76.35±15.63, 53~105) kg, all patients were not any dangerous events during the period of CPET and intensive control.①After intensive control, the static pulmonary function index, resting systolic blood pressure, rate blood pressure product and fasting blood glucose were significantly improved (P<0.05).②Before intensive control, the peak oxygen uptake is (55.60±15.69, 34.37~77.45) % pred and anaerobic threshold is (60.11±12.26, 43.29~80.63)% pred; after intensive control, the peak oxygen uptake is (71.85±21.04, 42.40~102.00) % pred and anaerobic threshold (74.95±17.03, 51.90~99.47) %pred. Compared with before the intensive control, the peak oxygen uptake and anaerobic threshold of all patients after intensive control were significantly increased by (29.09±7.38,17.78~41.80) % and(25.16±18.38, 1.77~81.86)%(all P<0.01). Other core indexes were also improved significantly, including peak oxygen uptake,peak heart rate, peak work rate, oxygen uptake efficiency plateau, lowest value of carbon dioxide ventilatory efficiency, slope of ventilatory equivalent for carbon dioxide, ramp exercise duration(all P<0.01).③In terms of individualized analysis, after intensive control, the above 8 CPET core indexes were all improved in 15 cases, and 7 indexes in 5 cases were improved; the peak oxygen uptakeof all cases increased by more than 15%, 16 cases > 20%, 13 cases > 25%, 10 cases > 30%. Conclusion: CPET can safely, objectively and quantitatively evaluate the overall functional status and therapeutic effects, and guide the formulation of individualized precise exercise intensity. The overall plan of individualized precision exercise for three months can safely and effectively reverse the overall functional status of patients with long-term cardio-cerebrovascular metabolism diseases.

[The impacts of outpatient vs inpatient holistic management based on exercise training on cardiac rehabilitation efficacy among patients with chronic heart failure].

Objective: To evaluate the impacts of outpatient vs inpatient exercise training (ET) on cardiac rehabilitation efficacy among patients with chronic heart failure (CHF). Methods: Thirty six patients who were diagnosed with CHF in Beijing Rehabilitation Hospital from September 2015 to September 2018, were randomly divided into three groups: control group (n=12), outpatient ET group (n=12) and inpatient ET group (n=12). Patients in control group were treated with conventional cardiac rehabilitation without ET, patients in outpatient and inpatient ET groups were treated with holistic cardiac rehabilitation with the core of ET according to individualized exercise prescription based on cardiopulmonary exercise testing (CPET). Exercise intensity of cycle ergometer was Δ50% power above anaerobic threshold (AT), 30 min/d, 5 d/week, for 12 weeks. General information, CPET parameters, echocardiogram, 6 minute walking distance (6MWD) and quality of life (QoL) score of three groups of patients before and after treatment were recorded. Results: All patients in 3 groups finished symptom-limited CPET and patients in ET groups finished 12 weeks - ET safely without complications. Before treatment, there were no significant differences in CPET parameters, echocardiogram results, 6MWD and QoL score among 3 groups (P>0.05). After treatment, AT (ml/min, ml/(min·kg), %pred), peak oxygen uptake (VO2) (ml/min, ml/(min·kg), %pred), peak oxygen pulse(ml/beat), peak workload(W/min, %pred), left ventricular ejection fraction (LVEF) and 6MWD of patients in outpatient and inpatient ET groups were significantly higher than those of patients in control group (P<0.05), QoL score of patients in outpatient and inpatient ET groups was lower than that of patients in control group(P<0.05). To be noted, there were no obvious differences in CPET indexes, echocardiogram results, 6MWD and QoL score in patients between outpatient ET group and inpatient ET group (P>0.05). For patients in control group, there were no significant differences in above parameters before and after treatment (P>0.05). AT(ml/min, ml/(min·kg)), Peak VO2 (ml/min, ml/(min·kg), %pred), peak oxygen pulse(ml/beat, %pred), peak workload(W/min, %pred), LVEF and 6MWD of patients in outpatient and inpatient ET groups were significantly higher than those before treatment (P<0.05), QoL score of patients in outpatient and inpatient ET groups after treatment was significantly lower than that before treatment (P<0.05). Conclusion: Outpatient ET can improve the cardiopulmonary function, exercise tolerance and QoL of CHF patients, which has no significant difference compared with inpatient ET, indicating that outpatient cardiac rehabilitation, as an effective rehabilitation mode, is deserved to be applied widely.

[Effects of cardiac rehabilitation protocol centered with personalized - exercise training on further improvement of holistic function in patients with coronary heart disease after percutaneous coronary intervention].

Objective: To investigate the effects of cardiac rehabilitation protocol centered with personalized - exercise training (ET) on further improvement of holistic function in patients with stable angina after percutaneous coronary intervention (PCI). Methods: 20 patients who were diagnosed with stable angina in Beijing Rehabilitation Hospital from June 2016 to December 2019, were randomly divided into control group (n=10) and ET group (n=10). All patients were received PCI selectively. After PCI, patients in Control group were treated with conventional cardiac rehabilitation without ET; patients in ET group were treated with ET-based cardiac rehabilitation for 12 weeks. Cardiopulmonary exercise testing (CPET) parameters, echocardiogram and 6-minute walking distance (6MWD) of 2 groups of patients were recorded respectively before PCI, 2 weeks after PCI and 12 weeks after ET. Results: All patients in 2 groups finished symptom limited maximum CPET, and patients in ET group finished 12 weeks - ET safely without complications. Before PCI and 2 weeks after PCI, there were no differences in parameters including anaerobic threshold (AT), peak oxygen uptake, peak oxygen pulse, left ventricular ejection fraction (LVEF) and 6MWD between control group and ET group（P>0.05）; after 12-week treatment, AT(ml/min,ml/(min·kg)), peak oxygen uptake(ml/(min·kg)), peak oxygen pulse(ml/beat) and 6MWD of patients in ET group were higher significantly than those of patients in control group (P<0.05). In ET group, the variables including AT (ml/min、ml/(min·kg)、%pred), peak oxygen uptake(ml/min,ml/(min·kg),%pred), peak oxygen pulse (ml/beat) and 6MWD of patients after 12-week ET were significantly higher than those of patients before PCI treatment (P<0.05); notably, AT (ml/(min·kg)) and peak oxygen uptake (ml/(min·kg)) of patients in ET group were significantly higher after 12-week ET program compared with those of patients 2 weeks after PCI ( P<0.05). In Control group, AT（ml/min）and peak oxygen pulse（ml/beat）of patients after 12-week treatment were higher than those of patients before PCI ( P<0.05), but there were no difference between 2 weeks after PCI and 12-week treatment ( P>0.05). Conclusion: Personalized - exercise training after PCI could further improve the cardiac function and exercise endurance, ET - based cardiac rehabilitation is an important part of secondary prevention for patients after PCI, which needs to be widely promoted.

Characterization of compression behaviors of high food waste content (HFWC) MSW and no food waste content (NFWC) MSW in China.

In this paper, three sets of laboratory tests were conducted on high-food-waste-content (HFWC-), no-food-waste-content (NFWC-) and decomposed (D-) MSWs to characterize their compression behaviors. The immediate compression ratios C'c were 0.30, 0.23 and 0.18 for HFWC-MSW, NFWC-MSW and D-MSW respectively, and tended to increase with the increasing food waste content of MSW. The release of intra-particle water contained in food waste contributed over 23.6-29.2% to immediate compression for HFWC-MSW. The mechanical creep ratios C'sc were 0.02, 0.015 and 0.01 for HFWC-MSW, NFWC-MSW and D-MSW respectively. A prediction model for C'sc was proposed which incorporated the effects of moisture content, dry unit weight and organic waste content. The bio-compression ratios C'sbI, C'sbII and C'sbIII in response to degradation stage I, II and III were 0.12, 0.10 and 0.02 for HFWC-MSW, and were 0.01, 0.15 and 0.01 for NFWC-MSW. Bio-compression is dominant in stage I and II and mechanical creep is the major contributor in stage III for HFWC-MSW, but to NFWC-MSW, mechanical creep is dominant in stage I and III, and bio-compression takes the main position in stage II. The bio-compression tended to increase linearly with leachate draining rate for HFWC-MSW, and the release of intra-particle water contributed 61.9-65.6% to bio-compression. A new model was proposed that can well capture the highly non-linear behavior of bio-compression for both HFWC-MSW and NFWC-MSW. Based on the above findings, the settlement behavior of HFWC-MSW and NFWC-MSW landfills was compared, and suggestions for technique-efficient and cost-effective design of a NFWC-MSW landfill were discussed.

Use of electrical resistivity tomography for detecting the distribution of leachate and gas in a large-scale MSW landfill cell.

In this study, integrate electrical resistivity tomography (ERT) tests were carried out in a large-scale (5.0 × 4.0 × 7.5 m) MSW landfill cell to investigate the possibility of detecting perched leachate mounds, leachate level, and gas accumulation zones at wet landfills. The resistivity of both bulk waste and waste components at different moisture states were measured and the three-phase volumetric relationships of the waste pile were analyzed to better interpret the ERT test results in the large-scale cell. The following observations were given: (1) The relationship between resistivity and volumetric moisture content (VMC) of waste sample can be reasonably fitted by Archie's law. The resistivity of waste components at a saturated state was all lower than 21 Ω m. (2) A significant amount of void gas was entrapped in the underwater waste, being 30.4-34.8% of the whole waste pile in volume. (3) Low-resistivity zones (< 5.0 Ω m) were observed in the waste pile being fully drained under a gravity condition, which was believed to be related to a perched leachate. (4) The average VMC values of the waste layer below and above the leachate level were in the ranges of 46.5-53.1% and 28.1-41.3%, respectively. (5) Irregular variations of high-resistivity zones (> 40 Ω m) observed in the underwater waste were associated with the accumulation and dissipation of gas pressure. It was found that the "gas-breaking value" in the gas accumulation zone was up to 10.5 kPa greater than the pore liquid pressure in the stable methanogenesis stage. These findings shone a light on the possibility of using the ERT method as an efficient tool for mapping the gas/leachate distribution and improving operations at wet landfills.

[Preliminary report of using cardiopulmonary exercise testing guide exercise rehabilitation in patients with chronic heart failure].

OBJECTIVE: The exercise rehabilitation in patient with chronic heart failure (CHF) is standard clinical practice, but it is rare using CardioPulmonary Exercise Testing (CPET) guide to prescribe exercise rehabilitation in China. METHODS: We performed symptom limited maximal CPET in 10 patients with CHF, randomly divided into two groups: 5 patients as control without exercise and 5 exercise patients used Δ50%W intensity to exercise 30 min/d, 5 d/w, x12 w. Before and after 12 w rehabilitation, we evaluated functions. RESULTS: There were no significant difference between two groups patients (P > 0.05). The exercise duration was increased from 8 min to 23 min after rehabilitation (P < 0.001); distance 6 minutes walking was increased from 394 m to 470 m (P < 0.05); score of Minnesota quality of life was decreased from 25 to 3 in exercise group (P < 0.01). However, there were nosignificant changes in control group (P>0.05) and their changes were smaller than those in exercise group (P < 0.01). CONCLUSION: The CPET guiding exercise rehabilitation is safe and effective for patients with CHF.

[Genetic characteristics of hemagglutinin in measles viruses isolated in Henan Province, China].

This study aims to investigate the genetic characteristics of hemagglutinin in wild-type measles viruses in Henan Province, China and to provide a basis for measles control and elimination. Specimens were collected from suspected measles cases in Henan during 2008-2012. Cell culture was performed for virus isolation, and RT-PCR was used to amplify hemagglutinin gene. The PCR products were sequenced and analyzed, including construction of phylogenetic tree and analysis of the distance between the isolated virus and the reference virus; then, the variations in predicted amino acids were analyzed. The results showed that 12 measles viruses were isolated in Henan Province and identified as H1a genotype; the nucleotide and amino acid homologies were 98.0%-100% and 97.2%-99.8%, respectively. One glycosylation site changed in all the 12 sequences because of the amino acid mutation from serine to asparagine at the 240th site, as compared with Edmonston-wt. USA/54/A. Overall, the wild-type measles virus genotype circulating in Henan Province from 2008 to 2012 was H1a, with high homology between strains; there were some variations in amino acid sequences, resulting in glycosylation site deletion.

Puerarin attenuates cerebral damage by improving cerebral microcirculation in spontaneously hypertensive rats.

Puerariae Lobatae Radix (Gegen in Chinese) is the dried root of Pueraria lobata, a semiwoody, perennial, and leguminous vine native to China. Puerarin is one of the effective components of isoflavones isolated from the root of Pueraria lobata. Previous studies showed that extracts derived from the root of Pueraria lobata possessed antihypertensive effect. Our study is to investigate whether puerarin contributes to prevention of stroke by improving cerebral microcirculation in rats. Materials and Methods. Video microscopy and laser Doppler perfusion imaging on the pia mater were used to measure the diameter of microvessel and blood perfusion in 12-week old spontaneously hypertensive rats (SHRs) and age-matched normotensive WKY rats. Histological alterations were observed by hematoxylin and eosin staining, and microvessel density in cerebral tissue was measured by immunohistochemical analysis with anti-Factor VIII antibody. Cell proliferation was detected by [(3)H]-TdR incorporation, and activities of p42/44 mitogen activated protein kinases (p42/44 MAPKs) were detected by western blot analysis in cultured cerebral microvascular endothelial cells (MECs). Results. Intravenous injection of puerarin relaxed arterioles and increased the blood flow perfusion in the pia mater in SHRs. Puerarin treatment for 14 days reduced the blood pressure to a normal level in SHRs (P < 0.05) and increased the arteriole diameter in the pia mater significantly as compared with vehicle treatment. Arteriole remodeling, edema, and ischemia in cerebral tissue were attenuated in puerarin-treated SHRs. Microvessel density in cerebral tissue was greater with puerarin than with vehicle treatment. Puerarin-treated MECs showed greater proliferation and p42/44 MAPKs activities than vehicle treatment. Conclusions. Puerarin possesses effects of antihypertension and stroke prevention by improved microcirculation in SHRs, which results from the increase in cerebral blood perfusion both by arteriole relaxation and p42/44 MAPKs-mediated angiogenesis.

Hypoxic preconditioning protects microvascular endothelial cells against hypoxia/reoxygenation injury by attenuating endoplasmic reticulum stress.

Endothelial cells (ECs) are directly exposed to hypoxia and contribute to injury during myocardial ischemia/reperfusion. Hypoxic preconditioning (HPC) protects ECs against hypoxia injury. This study aimed to explore whether HPC attenuates hypoxia/reoxygenation (H/R) injury by suppressing excessive endoplasmic reticulum stress (ERS) in cultured microvascular ECs (MVECs) from rat heart. MVECs injury was measured by lactate dehydrogenase (LDH) leakage, cytoskeleton destruction, and apoptosis. Expression of glucose regulating protein 78 (GRP78) and C/EBP homologous protein (CHOP), activation of caspase-12 (pro-apoptosis factors) and phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK) were detected by western blot analysis. HPC attenuated H/R-induced LDH leakage, cytoskeleton destruction, and cell apoptosis, as shown by flow cytometry, Bax/Bcl-2 ratio, caspase-3 activation and terminal deoxynucleotidyl transferase mediated dUTP-biotin nick end labeling. HPC suppressed H/R-induced ERS, as shown by a decrease in expression of GRP78 and CHOP, and caspase-12 activation. HPC enhanced p38 MAPK phosphorylation but decreased that of protein kinase R-like ER kinase (PERK, upstream regulator of CHOP). SB202190 (an inhibitor of p38 MAPK) abolished HPC-induced cytoprotection, downregulation of GRP78 and CHOP, and activation of caspase-12, as well as PERK phosphorylation. HPC may protect MVECs against H/R injury by suppressing CHOP-dependent apoptosis through p38 MAPK mediated downregulation of PERK activation.

Calcineurin mediates the protective effect of postconditioning on skeletal muscle.

We aimed to investigate whether ischemic postconditioning (I-postC) protects skeletal muscle against ischemia-reperfusion (I/R) injury through the calcineurin (CaN) pathway. Male Wistar rats underwent 4 h of right-hind-limb ischemia induced by clamping the femoral artery, then reperfusion for 2 h (I/R-2 h), 12 h (I/R-12 h), or 24 h (I/R-24 h) with or without I-postC. Ischemic postconditioning was induced by three cycles of 1-min reperfusion and 1-min ischemia at the onset of reperfusion after prolonged ischemia. The I-postC-24 h group was treated with or without cyclosporine A (a CaN inhibitor) 10 mg/kg per day for 3 days before artery occlusion. Cultured skeletal muscle cells (SMCs) from neonatal rats were exposed to 2-h hypoxia then 24-h reoxygenation (H/R), then postconditioned with two cycles of 10-min reoxygenation and 10-min hypoxia after prolonged hypoxia (hypoxia postconditioning [H-postC]) in the presence or absence of cyclosporine A. We observed the effects of activated CaN overexpression on apoptosis and viability of SMCs under H-postC. Ischemic postconditioning attenuated the increase in the level of malondialdehyde in skeletal muscle induced by I/R-2 h and I/R-24 h (P < 0.05) and lactate dehydrogenase in plasma induced by I/R-12 h and I/R-24 h (P < 0.05). Cyclosporine A abolished the protective role of I-postC in malondialdehyde level and lactate dehydrogenase leakage (P < 0.05, vs. I-postC group). Hypoxia postconditioning suppressed SMC apoptosis induced by H/R (P < 0.05, vs. H/R), which was accompanied by increased CaN expression. Cyclosporine A abolished the antiapoptotic effect of H-postC on SMCs (P < 0.05, vs. H-postC group). Overexpression of activated CaN strengthened the cytoprotection of H-postC (P < 0.05, vs. H-postC group). Ischemic postconditioning may protect skeletal muscle against I/R injury through the CaN pathway.

Cardiomyocyte-specific disruption of Serca2 in adult mice causes sarco(endo)plasmic reticulum stress and apoptosis.

Reduced sarco(endo)plasmic reticulum (SR) Ca(2+) ATPase (SERCA2) contributes to the impaired cardiomyocyte Ca(2+) homeostasis observed in heart failure. We hypothesized that a reduction in SERCA2 also elicits myocardial ER/SR stress responses, including unfolded protein responses (UPR) and cardiomyocyte apoptosis, which may additionally contribute to the pathophysiology of this condition. Left ventricular myocardium from mice with cardiomyocyte-specific tamoxifen-inducible disruption of Serca2 (SERCA2 KO) was compared with aged-matched controls. In SERCA2 KO hearts, SERCA2 protein levels were markedly reduced to 2% of control values at 7 weeks following tamoxifen treatment. Serca2 disruption caused increased abundance of the ER stress-associated proteins CRT, GRP78, PERK, and eIF2α and increased phosphorylation of PERK and eIF2α, indicating UPR induction. Pro-apoptotic signaling was also activated in SERCA2 KO, as the abundance of CHOP, caspase 12, and Bax was increased. Indeed, TUNEL staining revealed an increased fraction of cardiomyocytes undergoing apoptosis in SERCA2 KO. ER-Tracker staining additionally revealed altered ER structure. These findings indicate that reduction in SERCA2 protein abundance is associated with marked ER/SR stress in cardiomyocytes, which induces UPR, apoptosis, and ER/SR structural alterations. This suggests that reduced SERCA2 abundance or function may contribute to the phenotype of heart failure also through induction of ER/SR stress responses.

The calcineurin-myocyte enhancer factor 2c pathway mediates cardiac hypertrophy induced by endoplasmic reticulum stress in neonatal rat cardiomyocytes.

Endoplasmic reticulum (ER) stress (ERS) is involved in various cardiovascular diseases. Our previous study verified that ERS took part in the development of cardiac hypertrophy; however, its mechanism is still unclear. This study aimed to investigate the roles of the calcineurin (CaN) signal pathway in hypertrophy induced by the ERS inductor thapsigargin (TG) in neonatal cardiomyocytes from Sprague-Dawley rats. Investigation of ER chaperone expression, ER staining, and calreticulin immunofluorescence were used to detect the ERS response. mRNA expression of atrial natriuretic peptide and brain natriuretic peptide, total protein synthesis rate, and cell surface area were used to evaluate cardiac hypertrophy induced by TG. TG induced a significant ERS response along with hypertrophy in a dose- and time-dependent manner in cardiomyocytes, which was verified by treatment with tunicamycin, another ERS inducer. Furthermore, TG induced a significant elevation of the intracellular Ca(2+) level, CaN activation, and myocyte enhancer factor 2c (MEF2c) expression in a dose- and time-dependent manner in cardiomyocytes. Cyclosporine A, a CaN inhibitor, markedly suppressed MEF2c nuclear translocation and inhibited TG-induced hypertrophy. These results demonstrate that ERS induces cardiac hypertrophy and that the CaN-MEF2c pathway is involved in ERS-induced hypertrophy in cardiomyocytes.

[Effects of sarcoplasmic reticulum calcium ATPase 2a overexpression on endoplasmic reticulum stress in cardiomyocytes].

OBJECTIVE: To investigate the effects of sarcoplasmic reticulum calcium ATPase 2a (SERCA2a) overexpression on the endoplasmic reticulum stress (ERS). METHODS: Ventricular cardiomyocytes were obtained from a neonatal rat, cultured, and then randomly divided into 6 groups: normal control group; hypoxia group cultured in an airtight chamber gassed with 95% N(2)/5% CO2 at 37 degrees C for 72 hours so as to induce ERS; tunicamycin group treated with 10 microg/ml tunicamycin so as to induce ERS too; SERCA2a group transfected with recombinant adenovirus expressing the target gene SERCA2a (rAd-SERCA2a); SERCA2a + hypoxia group; and SERCA2a + tunicamycin group. Western blotting was used to detect the protein expression of SERCA2a, and glucose-regulated protein 78 (GRP78) and C/EBP homologous protein (CHOP), both the ERS markers. Flow cytometry was used to detect the apoptosis of the cardiomyocytes, and trypan blue staining was used to detect the survival rate of the cardiomyocytes. RESULTS: (1) The GRP78 expression level of the hypoxia group was 5.1 times as high as that of the control group, and the CHOP expression level of the hypoxia group was 2.5 times as high as hat of the control group. The GRP78 expression level of the tunicamycin group was 4.9 times as high as that of the control group, and the CHOP expression level of the tunicamycin group was 3.1 times as high as hat of the control group. SERCA2a overexpression was found to relieve the expression of GRP78 induced by hypoxia and tunicamycin (49.1% and 50.4% decrease respectively), and to inhibit the activation of CHOP (52.7% and 66.1% decrease respectively). (2) In comparison with the hypoxia group, the protein expression levels of GRP78 and CHOP of the SERCA2a overexpression + hypoxia group were significantly lower by 49.1% and 52.7% respectively, the apoptotic rate was significantly lower by 66.0%, and the cardiomyocyte survival rate was significantly higher by 13.4% (all P < 0.05). Compared with the tunicamycin group, the protein expression levels of GRP78 and CHOP of the SERCA2a overexpression + tunicamycin group were significantly lower by 50.4% and 66.1% respectively, the apoptotic rate was significantly lower by 54.0%, and the cardiomyocyte survival rate was significantly higher by 6.7% (all P < 0.05). CONCLUSION: SERCA2a overexpression attenuates ERS induced by hypoxia or tunicamycin, and protects cardiomyocytes against ERS-mediated cellular injury.

[C/EBP homologous protein-mediated endoplasmic reticulum stress-related apoptosis pathway is involved in abdominal aortic constriction-induced myocardium hypertrophy in rats.].

Endoplasmic reticulum stress (ERS) is an adaptive process in response to circumstantial changes, but excessive and/or prolonged ERS can induce cell apoptosis. C/EBP homologous protein (CHOP) is a very important marker participating in ERS-associated cell apoptosis, while the role of the myocyte apoptosis induced by CHOP remains unclear in the development of hypertrophy. The present study aimed to investigate the effect of CHOP-mediated ERS-associated apoptosis on myocardial hypertrophy induced by abdominal aortic constriction in rats. Healthy male Wistar rats were randomly divided into model group (n=45) and control group (n=40). The rats in model group received abdominal aortic constriction. Hemodynamic changes, whole heart weight/body weight (HW/BW) and left ventricular weight/body weight (LVW/BW) were measured on 1 d, 3 d, 7 d, 14 d and 28 d after surgery, respectively. The mRNA expression of glucose-regulated protein 78 (GRP78), calreticulin (CRT) and CHOP, which are important markers of ERS, were detected by RT-PCR, and Western blot was used to assess the protein level of GRP78, CRT, CHOP, and apoptosis-associated proteins, Bax and Bcl-2. The results obtained were as follows. Compared with control group, the blood pressure, LVW/BW, and HW/BW of rats in model group increased significantly and cardiac function enhanced compensatively on 7 d after surgery, and increased progressively during the experiment. As early as 1 d after surgery, the mRNA level of CRT in model group increased by 136% (P< 0.01) compared with control, while the protein expression increased by 69.2% on 7 d after surgery (P<0.01). Both mRNA and protein expression of GRP78 increased by 20% and 186% (P<0.01) respectively on 7 d after surgery, and the expression sustained high level during the experiment afterwards. Correlation analysis indicated a positive correlation between +dp/dt(max) and CRT protein expression (r=0.780, P<0.01) as well as GRP78 protein expression (r=0.694, P<0.01). Prolonged ERS triggered myocyte apoptosis, as both the mRNA and protein level of CHOP in model group increased by 22.2% (P<0.01) and 76.0% (P<0.01) respectively compared with control on 7 d after hypertrophy (14 d after surgery), and meanwhile, the protein expression of pro-apoptotic Bax increased by 41.1% (P<0.01) and anti-apoptotic Bcl-2 protein expression decreased by 25.5% (P<0.01). Correlation analysis indicated a positive correlation between CHOP and Bax expression (r=0.654, P<0.01), and a negative correlation between CHOP and Bcl-2 expression (r=-0.671, P<0.01). These results suggest that abdominal aortic constriction induces a significant up-regulation in ER molecular chaperones at early stage of post-surgery, indicating that ERS response is activated in the rat heart; while prolonged ERS could lead to myocyte apoptosis, and CHOP-mediated ERS-associated apoptosis may contribute to myocardial hypertrophy. We speculate that cell apoptosis may take part in the regulation of myocardial hypertrophy and heart failure, and determine the progression of decompensated hypertrophy.

[Cardioprotective mechanism of calreticulin up-regulation induced by hypoxic postconditioning.].

Calreticulin (CRT) is an essential Ca(2+)-binding chaperone existing in endoplasmic reticulum (ER) or sarcoplasmic reticulum (SR), and is involved in intracellular Ca(2+) homeostasis and protein folding. Ischemic postconditioning (I-postC), a newly discovered endogenous protective phenomenon, induces CRT up-regulation. The present study aimed to investigate the cardioprotective mechanism of CRT up-regulation induced by hypoxic postconditioning (H-postC). Primary cultured neonatal rat cardiomyocytes were exposed to 2 h of hypoxia followed by 24 h of reoxygenation. Postconditioning was carried out by two cycles of 10 min of reoxygenation and 20 min of rehypoxia after 2 h of hypoxia. Antisense oligodeoxynucleotides (AS-ODNs) were used to inhibit CRT expression 36 h before hypoxia. Cardiomyocytes were randomly divided into 6 groups as follows (n=4): control, hypoxia/reoxygenation (H/R), H-postC, AS, AS + H/R, and AS + H-postC. Morphological studies, lactate dehydrogenase (LDH) activity assay in culture medium, and flow cytometry were used to detect cardiomyocyte necrosis and apoptosis. Intracellular Ca(2+) concentration was detected by fluorescent Fluo-3/AM staining through laser confocal microscope, and p-nitrophenyl phosphate (PNPP) was used as substrate to measure calcineurin (CaN) activity. The expression of CRT, CaN, nuclear factor kappa B (NFκB) and apoptosis-related proteins, such as Bcl-2, Bax and C/EBP homologous protein (CHOP) were detected by Western blot. The results were as follows. (1) H-postC protected neonatal cardiomyocytes from H/R injury. Compared with H/R group, cell survival rate increased by 17.1%, apoptotic rate and LDH leakage decreased by 6.67% and 27.9% in H-postC group, respectively (P<0.05). (2) H-postC induced mild up-regulation of CRT expression. Inhibition of CRT by AS-ODNs attenuated the cardioprotection of H-postC partly. Compared with H-postC group, cell survival rate decreased by 8.98%, and apoptotic rate and LDH leakage increased by 1.74% and 13.6% in AS + H-postC group, respectively (P<0.05), but intracellular Ca(2+) concentration, CaN activity, and expression of CaN and NFκB did not change significantly (P>0.05), suggesting that CRT participates in endogenous protection, not through Ca(2+)-CaN pathway. (3) H-postC inhibited the expression of pro-apoptosis proteins such as Bax and CHOP, but induced up-regulation of anti-apoptosis protein Bcl-2. Inhibition of CRT by AS-ODNs partly inhibited the changes in apoptosis-related proteins expression induced by H-postC, suggesting that CRT participates in the anti-apoptosis effect of H-postC through regulating expression of apoptosis-related proteins. These results indicate that CRT up-regulation induced by H-postC is involved in the cardioprotection through regulating expression of apoptosis-related proteins, not through Ca(2+)-CaN pathway in neonatal cardiomyocytes.

[Genetic characterization of Chinese rubella virus isolates from 2003 to 2007].

57 rubella virus strains were isolated using Vero cell line or Vero/SLAM cell line from patients' throat swabs during rubella outbreaks and sporadics in 10 provinces of China from 2003 to 2007. Fragments of 1107 nucleotides of E1 genes of the isolates were amplified by RT-PCR, the PCR products were directly sequenced and analyzed. The phylogenetic analysis based on 739 nucleotides showed that out of 57 Chinese rubella virus strains, 55 belong to a distinguish branch of 1E genotype when comparing with 1E genotype rubella strains from other countries, and the other 2 Chinese rubella virus strains belong to 2B genotype. Most of the nucleotide mutations of 57 rubella viruses were silent mutations, and the amino acid sequences were highly conserved. Except one amino acid change (Thr212 --> Ser212) in two rubella viruses at the hemagglutination inhibition and neutralization epitopes, there had no change found at the important antigenic epitope sites of the other rubella viruses. 1E genotype rubella viruses isolated from 10 provinces of China from 2003 to 2007, and two imported 2B genotype rubella viruses from Vietnam suggested that 1E genotype was the predominant genotype in this period of time. The rubella virus genotypes circulated during 2003 to 2007 were different from that circulating during 1979 to 1984 and 1999 to 2002, the rubella prevailed in recent years was mainly caused by 1E genotype rubella viruses with multi-transmission routes.

Ischemic postconditioning protects myocardium from ischemia/reperfusion injury through attenuating endoplasmic reticulum stress.

Ischemic postconditioning (I-postC) is a newly discovered endogenous protective phenomenon capable of protecting the myocardium from I/R injury. The cardioprotective mechanisms of I-postC involve protein synthesis and preventing an increase in cytosolic calcium. Endoplasmic reticulum (ER) is a principal site for secretory protein synthesis and calcium storage. Myocardial I/R causes ER stress and perturbations of ER function. The purpose of the present study was to determine whether I-postC's attenuation of I/R injury involves reductions in ER stress through mitogen-activated protein kinase (MAPK) pathway. In the present study, models of rat myocardial I/R and hypoxia/reoxygenation (H/R) of neonatal rat cardiomyocytes were used. Myocardial infarct size was measured by triphenyltetrazolium chloride staining, and flow cytometry was used to quantitate cardiomyocyte apoptosis. Calreticulin expression and activation of caspase 12, p38 MAPK, and c-Jun NH2-terminal kinase (JNK) in myocardium or cardiomyocytes were detected by Western blots. It is found that I-postC protects the I/R heart against myocardial infarction, and hypoxic postconditioning protects neonatal cardiomyocytes from H/R-induced apoptosis. Ischemic postconditioning suppressed I/R-induced ER stress, as shown by a decrease in calreticulin expression and caspase 12 activation. Hypoxic postconditioning up-regulates p38 MAPK phosphorylation and down-regulates JNK phosphorylation in cardiomyocytes subjected to H/R. These results indicate that I-postC protects myocardium from I/R injury by suppressing ER stress, and that p38 MAPK and JNK pathways are associated with the I-postC-induced suppression of ER stress.

[Calreticulin is involved in ischemic postconditioning-induced attenuation of ischemia/reperfusion injury in rat skeletal muscle].

The present study was aimed to investigate the effect of ischemic postconditioning (I-postC) on ischemia/reperfusion (I/R) injury and whether calreticulin (CRT) is involved in its intracellular signal transduction both in vivo and in cultured skeletal muscle cells. I/R injury in the right hind limb of healthy male Wistar rats was induced by clamping the right femoral artery, and the rats were randomly divided into 3 groups (n=16): I/R group (4-hour ischemia/12- or 24-hour reperfusion), ischemic preconditioning (IPC) group (3 cycles of 1-minute ischemia/1-minute reperfusion) and I-postC group (3 cycles of 5-minute reperfusion/5-minute ischemia). The left hind limb was used as control. Lactate dehydrogenase (LDH) activity in blood plasma, wet/dry weight ratio (W/D) and ultramicrostructure of skeletal muscle were detected 12 h or 24 h after reperfusion. Cultured skeletal muscle cells from neonatal Sprague-Dawley (SD) rat were divided into 6 groups: hypoxia/reoxygenation (H/R) group, hypoxic postconditioning (H-postC) group, hypoxic preconditioning (HPC) group, cyclosporine A (CsA) + H-postC group, CsA + H/R group and control group. H/R was produced by 2-hour hypoxia/24-hour reoxygenation. The survival rate and apoptotic rate of skeletal muscle cells in each group were measured. Western blot was used to detect the expressions of CRT and calcineurin (CaN). The results were as follows: (1) During in vivo experiment, compared with I/R, I-postC significantly decreased LDH activity and W/D, attenuated the ultramicrostructure injury of skeletal muscle and the apoptosis of nucleolus. 12 h and 24 h after reperfusion, compared with that in I/R group, the expression of CRT in I-postC group increased by 439% and 102%, respectively (P<0.05), and the expression of CaN increased by 196% and 63%, respectively (P<0.05). Correlation analysis indicated a positive correlation between CRT and CaN expressions (r=0.865, P<0.01). (2) In cultured skeletal muscle cells, H-postC attenuated cell injury induced by H/R. Compared with those in H/R group, CRT and CaN expressions in H-postC increased by 31.8% (P<0.05) and 6.02%, respectively. The protection of H-postC and CaN up-regulation were eliminated when CsA, the inhibitor of CaN, was added before H-postC. Both in vivo and in vitro results indicate that I-postC, similar as IPC, can protect the skeletal muscle against I/R injury, and its effects may be mediated by CRT and CaN up-regulation. The inhibition of CaN expression may also attenuate the protective effects of I-postC.