[Establishment and efficiency test of a clinical prediction model of bronchopulmonary dysplasia associated pulmonary hypertension in very premature infants]

Objective: To develop a risk prediction model for identifying bronchopulmonary dysplasia (BPD) associated pulmonary hypertension (PH) in very premature infants. Methods: This was a retrospective cohort study. The clinical data of 626 very premature infants whose gestational age <32 weeks and who suffered from BPD were collected from October 1st, 2015 to December 31st, 2021 of the Seventh Medical Center of the People's Liberation Army General Hospital as a modeling set. The clinical data of 229 very premature infants with BPD of Hunan Children's Hospital from January 1 st, 2020 to December 31st, 2021 were collected as a validation set for external verification. The very premature infants with BPD were divided into PH group and non PH group based on the echocardiogram after 36 weeks' corrected age in the modeling set and validation set, respectively. Univariate analysis was used to compare the basic clinical characteristics between groups, and collinearity exclusion was carried out between variables. The risk factors of BPD associated PH were further screened out by multivariate Logistic regression, and the risk assessment model was established based on these variables. The receiver operating characteristic (ROC) area under curve (AUC) and Hosmer-Lemeshow goodness-of-fit test were used to evaluate the model's discrimination and calibration power, respectively. And the calibration curve was used to evaluate the accuracy of the model and draw the nomogram. The bootstrap repeated sampling method was used for internal verification. Finally, decision curve analysis (DCA) to evaluate the clinical practicability of the model was used. Results: A total of 626 very premature infants with BPD were included for modeling set, including 85 very premature infants in the PH group and 541 very premature infants in the non PH group. A total of 229 very premature infants with BPD were included for validation set, including 24 very premature infants in the PH group and 205 very premature infants in the non PH group. Univariate analysis of the modeling set found that 22 variables, such as artificial conception, fetal distress, gestational age, birth weight, small for gestational age, 1 minute Apgar score ≤7, antenatal corticosteroids, placental abruption, oligohydramnios, multiple pulmonary surfactant, neonatal respiratory distress syndrome (NRDS)>stage Ⅱ, early pulmonary hypertension, moderate-severe BPD, and hemodynamically significant patent ductus arteriosus (hsPDA) all had statistically significant influence between the PH group and the non PH group (all P<0.05). Antenatal corticosteroids, fetal distress, NRDS >stage Ⅱ, hsPDA, pneumonia and days of invasive mechanical ventilation were identified as predictive variables and finally included to establish the Logistic regression model. The AUC of this model was 0.86 (95%CI 0.82-0.90), the cut-off value was 0.17, the sensitivity was 0.77, and the specificity was 0.84. Hosmer-Lemeshow goodness-of-fit test showed that P>0.05. The AUC for external validation was 0.88, and the Hosmer-Lemeshow goodness-of-fit test suggested P>0.05. Conclusions: A high sensitivity and specificity risk prediction model of PBD associated PH in very premature infants was established. This predictive model is useful for early clinical identification of infants at high risk of BPD associated PH.

Systematically analysis of decompensated cirrhotic patients with spontaneous bacterial peritonitis to identify diagnostic and prognostic indexes

BACKGROUND

Spontaneous bacterial peritonitis (SBP) is a common complication in patients with cirrhosis. The diagnosis of SBP is still mostly based on ascites cultures and absolute ascites polymorphonuclear (PMN) cell count, which restricts the widely application in clinical settings. This study aimed to identify reliable and easy-to-use biomarkers for both diagnosis and prognosis of cirrhotic patients with SBP.

METHODS

We conducted a retrospective study including 413 cirrhotic patients from March 2013 to July 2022 in the First Affiliated Hospital of Guangxi Medical University. Patients' clinical characteristics and laboratory indices were collected and analyzed. Two machine learning methods (Xgboost and LASSO algorithms) and a logistic regression analysis were adopted to screen and validate the indices associated with the risk of SBP. A predictive model was constructed and validated using the estimated area under curve (AUC). The indices related to the survival of cirrhotic patients were also analyzed.

RESULTS

A total of 413 cirrhotic patients were enrolled in the study, of whom 329 were decompensated and 84 were compensated. 52 patients complicated and patients with SBP had a poorer Child-Pugh score (P < 0.05). Patients with SBP had a greater proportion of malignancies than those without SBP(P < 0.05). The majority of laboratory test indicators differed significantly between patients with and without SBP (P < 0.05). Albumin, neutrophil-to-lymphocyte ratio (NLR), and ferritin-to-neutrophil ratio (FNR) were found to be independently associated with SBP in decompensated cirrhotic patients using LASSO algorithms, and logistic regression analysis. The model established by the three indices showed a high predictive value with an AUC of 0.808. Furthermore, increased neutrophils, ALP, and C-reactive protein-to-albumin ratio (CAR) were associated with the shorter survival time of patients with decompensated cirrhosis, and the combination of these indices showed a greater predictive value for cirrhotic patients.

CONCLUSIONS

The present study identified FNR as a novel index in the diagnosis of SBP in decompensated patients with cirrhosis. A model based on neutrophils, ALP and CAR showed high performance in predicting the prognosis of patients with decompensated cirrhosis.

Influences of renal anemia on the pathology of IgA nephropathy: a study based on propensity score matching

OBJECTIVE

This study aims to investigate the influences of renal anemia on the pathogenesis of IgA nephropathy using propensity score matching (PSM).

METHODS

Renal biopsies from 462 patients with IgA nephropathy were enrolled in this study. PSM was used to balance intergroup covariates, and matching results were verified using a dot-plot of standardized mean differences and histograms of the propensity score distribution and distance distribution. The matched data were used to analyze the impact of renal anemia on the pathological indicators of IgA nephropathy by logistic regression.

RESULTS

A total of 132 pairs of patients from the renal anemia group and the non-renal anemia group were matched by PSM; after matching, the standard deviations of 13 covariates were within 0.25. Multivariate logistic regression results suggested that the CKD4-5 stage of IgA nephropathy and tubular atrophy/interstitial fibrosis >50% were independent risk factors for renal anemia.

CONCLUSIONS

Via PSM, we demonstrated that decreased eGFR and severe tubular atrophy/interstitial fibrosis are correlated with renal anemia in IgA nephropathy. In clinical practice, renal anemia in patients with IgA nephropathy of CKD3 stage or above should be closely monitored and managed.

Impact of UGT2B7 and ABCC2 genetic polymorphisms on mycophenolic acid metabolism in Chinese renal transplant recipients

AIM

To evaluate genetic variants affecting mycophenolic acid (MPA) metabolism in Chinese renal transplant recipients.

METHODS

Total 11 SNPs of UGT1A9, UGT1A8, UGT2B7, ABCC2, ABCG2 and SLCO1B3 were genotyped in 408 Chinese renal transplant recipients. Associations between SNPs and MPA concentration/dose ratio (C₀/D) were analyzed using different genetic models. Multivariate linear regression was used to analyze associations between log (C₀/D) and clinical factors. Results: After adjustment by clinical factors, UGT2B7 rs7662029 was associated with log (C₀/D) using a dominant (p = 0.041) and an additive (p = 0.038) model, ABCC2 rs717620 was associated with log (C₀/D) using a recessive model (p = 0.019). Using additive model, SNP-SNP interactions were identified (p = 0.002) between ABCC2 rs717620 and UGT1A9 rs2741049, with interactions (p = 0.002) between ABCC2 rs717620 and UGT1A8 rs1042597. Age, albumin and serum creatinine were associated with log (C₀/D).

CONCLUSION

rs7662029 and rs717620 may affect MPA pharmacokinetics. SNP-SNP interactions and clinical factors may have significant effects on MPA metabolism.

Albuminuria and Endothelial Dysfunction in Patients with Non-Diabetic Chronic Kidney Disease

BACKGROUND Albuminuria has been associated with cardiovascular events, but whether such an association can be explained by endothelial dysfunction is not fully understood. In this study, we examined the relationship between the urine albumin-to-creatinine ratio (UACR) and biomarkers of endothelial function in patients with chronic kidney disease (CKD). MATERIAL AND METHODS The cross-sectional associations of renal dysfunction and UACR with procoagulant and inflammatory factors were evaluated for 151 consecutive CKD (stage 3-5) patients. Subjects were grouped by UACR (≤300 mg/g or >300 mg/g) and estimated glomerular filtration rate (eGFR) (30≤ eGFR <60, 15≤ eGFR <30, or eGFR <15 ml/min per 1.73 m²). RESULTS A higher UACR level was associated with an increase in von Willebrand factor antigen (vWF: Ag) levels, vWF activity, factor VIII, interleukin-2, and log (interleukin-6), even after adjustment for risk factors. Linear regression analysis indicated that for every 88.5 mg/g increase in UACR, the vWF activity and factor VIII were elevated by 8.3% and 6.3%, respectively. The factorial design ANOVA data showed no statistically significant interaction between UACR and CKD stage with procoagulant and inflammatory factors. CONCLUSIONS Our study shows an eGFR-independent association of higher UACR with elevations in markers of endothelial dysfunction and inflammatory factors in CKD patients.

Protective Effects and Mechanisms of Shenhua Tablet () on Toll-Like Receptors in Rat Model of Renal Ischemia-Reperfusion Injury

OBJECTIVES

To investigate the protective effects and potential mechanisms of Shenhua Tablet (, SHT) on the toll-like receptors (TLRs)-mediated signaling pathways in a rat model of kidney ischemia-reperfusion injury (IRI).

METHODS

Sixty male Wistar rats were randomly divided into 5 groups: sham surgery, model control, astragaloside (150 mg•kg^-1•d^-1), low- and high-dose SHT (1.5 and 3.0 g•kg^-1•d^-1, repectively) groups. One week after drug treatment, rats underwent surgery to establish the IRI models. At 24 h and 72 h after the modeling, serum creatinine (Scr) and blood urea nitrogen (BUN) were analyzed; pathological damage were scored after periodic acid-Schiffstaining. TLR2, TLR4 and myeloid differentiation factor 88 (MyD88) protein and mRNA expressions were detected by inmmunohistochemistry, Western blot and qPCR. Tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6) protein expressions were detected by enzyme linked immunosorbent assay.

RESULTS

Compared with the sham group, the model group exhibited severe change in renal function (Scr: 189.42±21.50, P<0.05), pathological damage (damage score: 4.50±0.55, P<0.05), and the expression levels of TLR2, TLR4, MyD88, TNF-α, IL-6 were significantly higher than other groups. Meanwhile, the levels of TLRs in model group showed upward tendency from 24 to 72 h, unparalleled with pathological and functional changes. The aforementioned parameters were alleviated to a certain extent, and, in addition to TLRs, presented the obvious downward trending from the 24 to 72 h after the intervention in the SHT and astragaloside groups relative to the model (P<0.05); in particular, the most significant mitigation of these changes was observed in the SHT-H group (P<0.05).

CONCLUSION

TLRs may be an important spot to treat and research in acute kidney injury. SHT could effectively mitigate renal injuries and promote recovery of IRI injuries through suppression of degeneration induced by up-regulation of TLR2 and TLR4 expression levels in the MyD88-dependent signaling pathway and exhibit some dose dependence.

Decreased Serum C3 Levels in Immunoglobulin A (IgA) Nephropathy with Chronic Kidney Disease: A Propensity Score Matching Study

Background

The effects of low serum C3 levels and the activation of the complement system on the development and the prognosis of IgAN are unclear. The present study aimed to determine whether decreased levels of complement C3 influence the prognosis of IgAN patients with chronic kidney disease.

Material/Methods

We enrolled a total of 1564 patients with primary IgAN diagnosed by renal biopsy at the Chinese PLA General Hospital from January 2011 to March 2015. The endpoint was end-stage renal disease (ESRD) or a doubling of the baseline serum creatinine (D-SCr) level. All patients were using 1: 1 propensity score matching (PSM), and the baseline values were not significantly different between these 2 groups (P>0.05).

Results

During a follow-up period, 14 patients in the group with decreased C3 levels reached the endpoint, with 12 patients with normal C3 levels. There was no significant difference between the 2 groups in achieving D-SCr or ESRD (P=0.676). In multivariate Cox analysis, adjusted for demographic and laboratory examination, the risk of reaching the endpoint was comparable in the 2 groups (HR, 0.70; 95% CI, 0.27–1.78; P=0.449;). Furthermore, the risk of reaching ESRD (HR, 0.83; 95% CI, 0.25–2.75; P=0.757) and D-SCr (HR, 1.45; 95% CI, 0.20–10.60; P=0.718) did not differ between the 2 groups.

Conclusions

Decreased serum C3 levels in IgA nephropathy with chronic kidney disease did not play a decisive role in renal progression.

Protective effects of astragaloside in rats with adriamycin nephropathy and underlying mechanism

The present study was designed to determine the mechanism underlying the treatment of nephrotic syndrome using astragaloside by observing the effects of astragaloside on the expression of nephrin and podocin proteins and genes in kidneys of rats with adriamycin nephropathy. The rats were injected with adriamycin and, after successful model establishment, randomly divided into a model group, a Methylprednisolone (MP) group, and an astragaloside group. The 24-h complete urine samples were collected. Biochemical indicators were monitored, and kidney tissues were collected for pathological analysis using light microscopy and electron microscopy. The mRNA expression of nephrin and podocin was measured in the kidney tissues using the real-time qPCR, and the protein expression levels of nephrin and podocin were detected using Western blot analysis. At the end of 12 weeks of drug intervention, the urinary protein level was lower in the MP and astragaloside groups than that in the model group (P = 0.008 and P = 0.01, respectively). Serum albumin was higher in the MP and astragaloside groups than in the model group (P < 0.001 and P = 0.012, respectively). Podocytes in the MP group were nearly normal, and fusion of podocytes in the astragaloside group was significantly less than that in the control group. The nephrin and podocin mRNA and protein expression levels in the intervention groups were higher (P < 0.05) than that in the model group. Due to the increased expression of podocyte-related nephrin and podocin proteins, astragaloside maintained slit diaphragm integrity and decreased the level of proteinuria in rats with adriamycin nephropathy.

Genetic Polymorphisms of 21 STR Loci in Hunan Province-based Han Population

OBJECTIVES

To investigate the genetic polymorphisms of 21 short tandem repeat （STR） loci （D3S1358, D13S317, D7S820, D16S539, Penta E, D2S441, TPOX, TH01, D2S1338, CSF1PO, Penta D, D10S1248, D19S433, vWA, D21S11, D18S51, D6S1043, D8S1179, D5S818, D12S391 and FGA）.

METHODS

A total of 560 blood samples were collected from unrelated healthy individuals of Han population in Hunan Province. Chelex-100 extraction method was applied to the extraction of genomic DNA, and an AGCU EX22 Kit and 9700 STR amplification was used in amplification reactions. The products were separated and analyzed on 310 Genetic Analyzer.

RESULTS

A total of 248 alleles were observed, the allelic frequencies ranging from 0.001 to 0.518. Observation of genotype distributions for each locus showed no deviations from Hardy-Weinberg equilibrium except Penta E （P=0.023）. The combined power of discrimination, combined power of exclusion, and combined matching probability of the 21 STR loci were approximately 0.999 999 999 999 999 999 999 999 8, 0.999 999 998, and 1.36×10⁻²⁵, respectively.

CONCLUSIONS

The 21 STR loci show high polymorphisms in the Han population, which can provide valuable data and a theoretical basis for forensic individual identification and paternity testing.

Construction of p66Shc gene interfering lentivirus vectors and its effects on alveolar epithelial cells apoptosis induced by hyperoxia

Background

The aim of this study is to observe the inhibitive effects of p66Shc gene interfering lentivirus vectors on the expression of p66Shc, and to explore its effects on alveolar epithelial cells apoptosis induced by hyperoxia.

Methods

The gene sequences were cloned into the pLenR-GPH-shRNA lentiviral vector, which was selected by Genebank searches. The pLenR-GPH-shRNA and lentiviral vector packaging plasmid mix were cotransfected into 293T cells to package lentiviral particles. Culture virus supernatant was harvested, and then the virus titer was determined by serial dilution assay. A549 cells were transduced with the constructed lentiviral vectors, and real-time polymerase chain reaction (RT-PCR) and Western blot were used to evaluate p66Shc expression. This study is divided into a control group, a hyperoxia group, an A549-p66ShcshRNA hyperoxia group, and a negative lentivirus group. Cell apoptosis was detected by flow cytometry after 24 hours; the expression of X-linked inhibitor of apoptosis protein (XIAP) and caspase-9 were detected by immunohistochemistry assay. The production of reactive oxygen species and cellular mitochondria membrane potential (ΔΨm) were determined by fluorescence microscopy.

Results

We successfully established the p66Shc gene interfering lentivirus vectors, A549-p66ShcshRNA. The A549-p66ShcshRNA was transfected into alveolar epithelial cells, and the inhibitive effects on the expression of p66Shc were observed. Both RT-PCR and Western blot demonstrated downregulation of p66Shc expression in A549 cells. In the A549-p66ShcshRNA hyperoxia group, we found dampened oxidative stress. A549-p66ShcshRNA can cause p66Shc gene silencing, reduce mitochondrial reactive oxygen species generation, reduce membrane potential decrease, reduce the apoptosis of A549 cells, and reduce alveolar epithelial cell injury, while the lentiviral empty vector group had no such changes.

Conclusion

p66Shc gene interfering lentivirus vector can affect the alveolar epithelial cells apoptosis induced by hyperoxia.

[Analysis of clinical effects of three operative methods for osteoporotic vertebral compression fracture]

OBJECTIVE

To explore the clinical outcomes of percutaneous vertebroplasty(PVP), percutaneous kyphoplasty(PKP) and percutaneous hollow pedicle screw with lateral holes implanted bone cement reinforcement in treating osteoporotic vertebral compression fracture(OVCF).

METHODS

From May 2012 to November 2013, the clinical data of 90 patients with osteoporotic vertebral compression fracture were retrospectively analyzed. According to the different methods of operation, the patients were divided into three groups, including the percutaneous hollow pedicle screw with lateral holes implanted bone cement reinforcement group (group A), percutaneous vertebroplasty group (group B), percutaneous kyphoplasty group (group C), each group had 30 patients. Pre operative, postoperative at 1 day, 3 months, 1 year, the back pain was assessed by visual analogue scale(VAS), and vertebral height compression ratio, Cobb angle were measured by X-rays.

RESULTS

All operations were successful and no complications such as postoperative infections and deep vein thrombosis were found. At the final follow up, there were 2 patients with mild postoperative back pain in group A;7 patients with moderate postoperative back pain, 4 patients with severe postoperative back pain, 2 patients with postoperative vertebral refracture in group B; 5 patients with moderate postoperative back pain, 3 patients with severe postoperative back pain, 4 patients with postoperative vertebral refracture in group C. Postoperative VAS, vertebral height compression ratio, Cobb angle of all patients have obviously improved than preoperative(P<0.05). On 1 day, 3 months, 1 year after operation, there was significant difference between group A and group B, C(P<0.05), there was no significant difference between group B and group C(P>0.05). There was no significant difference in group A above items and different times(P>0.05), and there was significant difference in group B, C above items and different times(P<0.05).

CONCLUSIONS

The effect of PVP and PKP on the immediately postoperative pain relief was more than percutaneous hollow pedicle screw with lateral holes implanted bone cement reinforcement in treating osteoporotic vertebral compression fracture, but, residual back pain can happen in different extent in the patients underwent PVP and PKP. Percutaneous hollow pedicle screw with lateral holes implanted bone cement reinforcement technique has obvious advantage in recovery of the vertebral height, correction of vertebral deformity, reduction of postoperative back pain.

[Resveratrol increases sirtuin 1 expression in peripheral blood mononuclear cells of premature infants and inhibits the oxidative stress induced by hyperoxia in vivo]

OBJECTIVE

To explore the effect of resveratrol on the levels of sirtuin 1 (SIRT1) and reactive oxygen species (ROS) in peripheral blood mononuclear cells (PBMCs) of premature infants exposed to hyperoxia.

METHODS

Peripheral blood and isolated PBMCs from premature infants (gestational age<32 weeks) without oxygen supplement were collected and were randomly assigned into four groups: control, air+resveratrol, hyperoxia, and hyperoxia+resveratrol. The PBMCs were cultured in vitro for 48 hours, then the ROS content in PBMCs was measured by laser scanning confocal microscopy. Malondialdehyde (MDA) content in the medium was measured by the whole spectrum spectrophotometer. SIRT1 positioning was assessed by immunofluorescence. SIRT1 expression levels in PBMCs were measured by Western bolt.

RESULTS

Compared with the control group, the level of SIRT1 in the air+resveratrol group increased significantly (P<0.05). The levels of ROS and MDA and the SIRT1 transposition rate in the hyperoxia group increased significantly, while the expression level of SIRT1 decreased significantly compared with the control group (P<0.05). The levels of ROS and MDA and the SIRT1 transposition rate decreased significantly (P<0.05), and the expression level of SIRT1 increased significantly in the hyperoxia+resveratrol group (P<0.05).

CONCLUSIONS

Resveratrol can increase SIRT1 expression in PBMCs and inhibit SIRT1 shuttle from nucleus to cytoplasm in order to increase the ability of antioxidative stress in premature infants exposed to hyperoxia, thereby reducing the oxidative stress injury in premature infants.

[Resveratrol increases sirtuin 1 expression in peripheral blood mononuclear cells of premature infants and inhibits the oxidative stress induced by hyperoxia in vivo]

OBJECTIVE

To explore the effect of resveratrol on the levels of sirtuin 1 (SIRT1) and reactive oxygen species (ROS) in peripheral blood mononuclear cells (PBMCs) of premature infants exposed to hyperoxia.

METHODS

Peripheral blood and isolated PBMCs from premature infants (gestational age<32 weeks) without oxygen supplement were collected and were randomly assigned into four groups: control, air+resveratrol, hyperoxia, and hyperoxia+resveratrol. The PBMCs were cultured in vitro for 48 hours, then the ROS content in PBMCs was measured by laser scanning confocal microscopy. Malondialdehyde (MDA) content in the medium was measured by the whole spectrum spectrophotometer. SIRT1 positioning was assessed by immunofluorescence. SIRT1 expression levels in PBMCs were measured by Western bolt.

RESULTS

Compared with the control group, the level of SIRT1 in the air+resveratrol group increased significantly (P<0.05). The levels of ROS and MDA and the SIRT1 transposition rate in the hyperoxia group increased significantly, while the expression level of SIRT1 decreased significantly compared with the control group (P<0.05). The levels of ROS and MDA and the SIRT1 transposition rate decreased significantly (P<0.05), and the expression level of SIRT1 increased significantly in the hyperoxia+resveratrol group (P<0.05).

CONCLUSIONS

Resveratrol can increase SIRT1 expression in PBMCs and inhibit SIRT1 shuttle from nucleus to cytoplasm in order to increase the ability of antioxidative stress in premature infants exposed to hyperoxia, thereby reducing the oxidative stress injury in premature infants.

Renal Protective Effect of Probucol in Rats with Contrast-Induced Nephropathy and its Underlying Mechanism

Background

Contrast-induced nephropathy (CIN) refers to acute renal damage that occurs after the use of contrast agents. This study investigated the renal protective effect of probucol in a rat model of contrast-induced nephropathy and the mechanism of its effect.

Material/Methods

Twenty-eight Wistar rats were randomly divided into the control group, model group, N-acetylcysteine(NAC) group, and probucol group. We used a rat model of iopromide-induced CIN. One day prior to modeling, the rats received gavage. At 24 h after the modeling, blood biochemistry and urine protein were assessed. Malondialdehyde (MDA) and superoxide dismutase (SOD) were measured in renal tissue. Kidney sections were created for histopathological examination.

Results

The model group of rats showed significantly elevated levels of blood creatinine, urea nitrogen, 24-h urine protein, histopathological scores, and parameters of oxidative stress (P<0.05). Both the NAC and probucol groups demonstrated significantly lower Scr, BUN, and urine protein levels compared to the model group (P<0.05), with no significant difference between these 2 groups. The NAC group and the probucol group had significantly lower MDA and higher SOD than the model group at 24 h after modeling (P<0.05). The 8-OHdG-positive tubule of the probucol group and NAC group were significantly lower than those of the model group (p=0.046, P=0.0008), with significant difference between these 2 groups (P=0.024).

Conclusions

Probucol can effectively reduce kidney damage caused by contrast agent. The underlying mechanism may be that probucol accelerates the recovery of renal function and renal pathology by reducing local renal oxidative stress.

[Silencing of Pin1 suppresses hyperoxia-induced apoptosis of A549 cells]

OBJECTIVE

To explore the effect of silence of Pin1 expression on hyperoxia-induced apoptosis in alveolar epithelial cells A549.

METHODS

A549 cells were divided into four groups: control, hyperoxia, negative lentivirus and Pin1-shRNA hyperoxia. The hyperoxia group was exposed to a mixture of 95%O2 and 5%CO2 for 10 minutes. Then cells were cultured in a closed environment. After 24 hours, the changes of morphology were observed under an inverted microscope. Cell apoptosis was detected by flow cytometry (FCM). The expression of X-linked inhibitor of apoptosis protein (XIAP) and Caspase-9 were detected by immunohistochemistry. The production of reactive oxygen species (ROS) and cellular mitochondria membrane potential (△Ψm) were determined by fluorescence microscopy.

RESULTS

Under the inverted microscope, the A549 cells grew slowly and the changes in morphology of the cells were most obvious in the hyperoxia and negative lentivirus groups. The changes in morphology of A549 cells were obviously improved in the Pin1-shRNA hyperoxia group. The FCM results showed that the apoptosis rate of A549 cells increased, Caspase-9 expression increased, XIAP expression decreased, mitochondrial ROS production increased and mitochondrial membrane potential decreased in the hyperoxia and negative lentivirus groups compared with the control group (P<0.05). Compared with the hyperoxia and negative lentivirus groups, the apoptosis rate of A549 cells decreased, Caspase-9 expression decreased, XIAP expression increased, mitochondrial ROS production decreased and mitochondrial membrane potential increased in the Pin1-shRNA hyperoxia group (P<0.05), although the levels of the indexes did not reach to those of the control group.

CONCLUSIONS

Silencing of Pin1 could suppress hyperoxia-induced apoptosis of A549 cells.

Pretreatment of mesenchymal stem cells with angiotensin II enhances paracrine effects, angiogenesis, gap junction formation and therapeutic efficacy for myocardial infarction

BACKGROUND

Pretreatment of mesenchymal stem cells (MSCs) with growth factors is reported to be an effective route for improving cell-based therapy of myocardial infarction (MI). Angiotensin II (Ang II) triggers vascular endothelial growth factor (VEGF) synthesis in MSCs. This study aimed to investigate the effects and mechanisms of Ang II pretreatment in enhancing the therapeutic efficacy of MSCs in MI.

METHODS

MSCs and endothelial cells (ECs) were isolated from Sprague-Dawley rats. After pretreated with or without 100 nM of Ang II for 24 h, the MSCs were directly injected into the border zones of the ischemic heart. Cardiac function, fibrosis, infarct size, VEGF expression, angiogenesis, and cell differentiation in the infarcted myocardium were determined after 30 days. The cell apoptosis of MSCs post hypoxia was assessed using flow cytometry. The angiogenic activity of MSCs was analyzed using tube formation assay. The gap junction protein connexin-43 (Cx43) expression was detected.

RESULTS

Compared with the MSC group, pretreatment of MSCs with Ang II resulted in better cardiac function, less cardiac fibrosis, smaller infarct size, and higher expression of VEGF and Von Willebrand Factor in ischemic myocardium, but no promotion of cardiomyocyte-like differentiation of MSCs. Ang II pretreatment enhanced the survival of MSCs and the H9c2 cells surrounding MSCs, and augmented the tube formation of ECs and MSCs. Ang II pretreatment up-regulated the Cx43 expression.

CONCLUSIONS

The pretreatment of MSCs with Ang II improved the outcome of MSC-based therapy for MI via the mechanisms of enhancing the paracrine production of VEGF, angiogenesis, and gap junction formation.

[Roles of PKCβ/P66Shc oxidative stress signal pathway in mediating hyperoxia-induced ROS production in alveolar epithelial cells]

OBJECTIVE

To explore the roles of PKCβ/P66Shc oxidative stress signal pathway in mediating hyperoxia-induced reactive oxgen species (ROS) production in alveolar epithelial cells (A549) and the protective effects of PKCβ inhibitor on hyperoxia-induced injuries of alveolar epithelial cells.

METHODS

A549 cells were cultured in vitro and randomly divided into three groups: control, hyperoxia and PKCβ inhibitor LY333531 treatment. The hyperoxia group was exposed to a mixture of O2 (950 mL/L) and CO2 (50 mL/L) for 10 minutes and then cultured in a closed environment. The LY333531 group was treated with PKCβ inhibitor LY333531 of 10 µmol/L for 24 hours before hyperoxia induction. Cells were collected 24 hours after culture and the levels of PKCβ, Pin1, P66Shc and P66Shc-Ser36 were detected by Western blot. The intracellular translocation of P66Shc, the production of ROS and cellular mitochondria membrane potential were measured using the confocal microscopy.

RESULTS

Compared with the control group, the levels of PKCβ, Pin1, P66Shc and P-P66Shc-Ser36 in A549 cells 24 hours after culture increased significantly in the hyperoxia group. These changes in the hyperoxia group were accompanied with an increased translocation rate of P66Shc from cytoplasm into mitochondria, an increased production of mitochondrial ROS, and a reduced mitochondrial membrane potential. Compared with the hyperoxia group, the levels of Pin1, P66Shc and P66Shc-Ser36 in A549 cells, the translocation rate of P66Shc from cytoplasm into mitochondria and the production of mitochondrial ROS decreased significantly, while the mitochondrial membrane potential increased significantly in the LY333531 treatment group. However, there were significant differences in the above mentioned measurements between the LY333531 treatment and control groups.

CONCLUSIONS

Hyperoxia can increase the expression of PKCβ in alveolar epithelial cells and production of mitochondrial ROS and decrease mitochondrial membrane potential. PKCβ inhibitor LY333531 can partially disrupt these changes and thus alleviate the hyperoxia-induced alveolar epithelial cell injury.

Cryopreservation of gemmae of Marchantia polymorpha L. (Marchantiophyta, Marchantiaceae) without prior pretreatment

BACKGROUND

Successful cryopreservation of gametophytic material of bryophytes requires pretreatment with sucrose or abscisic acid. Compared to gametophyte materials, spore and gemmae cryopreservation may be more efficient, simple and stable systems for storing large amounts of genetic diversity of bryophytes within a small space. However, there has still been no attempt at cryopreserving bryophyte gemmae.

OBJECTIVE

The aim of this study is to determine whether bryophyte gemmae with differing levels of desiccation tolerance could survive and germinate after cryopreservation without prior encapsulation and pretreatment.

MATERIALS AND METHODS

Gemmae of Marchantia polymorpha L. were dried with silica gel for different times and then rapidly cooled in liquid nitrogen.

RESULTS

The germination level of fresh gemmae was 95 % After 3 h predrying and 1 d in LN, germination was 68 % and was still up to 59 % after storage for 75 days.

CONCLUSION

We conclude that the natural desiccation tolerance of bryophyte gemmae permits cryopreservation without prior pretreatment other than drying.

Upregulation of arginase activity contributes to intracellular ROS production induced by high glucose in H9c2 cells

Arginase is upregulated in some tissues under diabetes states. Arginase can compete with nitroxide synthase (NOS) for the common substrate L-arginine and thus increases oxidative stress by NOS uncoupling. We want to analyze whether arginase is upregulated and contribute to oxidative stress in H9c2 cells during high glucose treatment. H9c2 cells were cultured in normal or high glucose DMEM. Arginase activity increased in parallel with increased cell death and oxidative stress. Arginase inhibitor N ω-hydroxy-nor-l-arginine (nor-NOHA) and NOS inhibitor N ω-nitro-l-arginine methyl ester (L-NAME) could reverse these effects. Despite of upregulated NOS activity, NO production was impaired which could be preserved by nor-NOHA, suggesting a decreased substrate availability of NOS due to increased arginase activity. L-arginine supplementation decreased superoxide production while it could not protect cells from death. Upregulated arginase activity in H9c2 treated with high glucose can cause NOS uncoupling and subsequently reactive oxygen species augmentation and cell death. These findings suggest that arginase will be a novel therapeutic target for treatment of diabetic cardiomyopathy.

Efficacy of paralleled clipping of rectal ligament in resection of rectal cancer in elderly obese male patients

AIM: To evaluate the efficacy of paralleled clipping of rectal ligament in resection of rectal cancer in elderly obese male patients.

METHODS: Ninety-two elderly obese male patients with rectal cancer were randomly divided into either a control group or an experimental group, with 46 patients in each group. The control group underwent regular handling of rectal ligament in resection of rectal cancer, while the experimental group underwent paralleled clipping of rectal ligament. Intraoperative and postoperative indices were compared between the two groups.

RESULTS: The operative time and the rate of rectal ulceration were significantly lower in the experimental group than in the control group (67.2 min ± 10.3 min vs 124.8 min ± 11.8 min, 0.0% vs 15.2%, t = 24.942, χ² = 7.577, P = 0.000, 0.006). There was no significant difference in intraoperative bleeding and the rate of ureteral injury between the two groups (157.9 mL ± 26.2 mL vs 154.2 mL ± 27.4 mL, 2.2% vs 4.3%, t = 0.662, χ² = 0.662, 0.345, P = 0.510, 0.557). The rates of mesorectal disintegrity and pelvic infection were significantly lower in the experimental group than in the control group (2.2% vs 17.4%, 4.3% vs 19.6%, χ² = 6.035, 5.060, P = 0.014, 0.024).

CONCLUSION: Paralleled clipping of rectal ligament in resection of rectal cancer can reduce surgical difficulty and improve surgical safety in elderly obese male patients.

Hypoxia decreased chemosensitivity of breast cancer cell line MCF-7 to paclitaxel through cyclin B1

Hypoxia, frequently found in the center of solid tumors, may lead to enhance the production of key factor in cell survival, invasion, angiogenesis and loss of apoptosis. The low oxygen tension in hypoxic tumors is also known to interfere with the efficacy of chemotherapy, but the underlying mechanisms are not very clear. Paclitaxel (PTX) is an active agent used in breast cancer chemotherapy, which disturbs microtubule dynamics and impairs the transition of cells from metaphase to anaphase in mitosis, leading to cell death by apoptosis. In the present study, we try to determine whether hypoxia can decrease the chemosensitivity of human breast carcinoma cells to PTX and elucidate the underlying mechanism. We found that hypoxia could decrease PTX-induced cell death and G(2)/M arrest. Furthermore, our results showed that hypoxia inhibit PTX-induced soluble tubulin polymerized. In addition, we also found hypoxia could suppress PTX-induced cell cycle protein-cyclin B1 expression in MCF-7 cells. To further investigate whether the inhibitory effect of hypoxia on PTX-induced cell death is mediated by decreasing levels of cyclin B1, cyclin B1-transfected MCF-7 cells were used under hypoxic condition. The data showed that the hypoxia-based decreasing chemosensitivity of breast cancer cells to PTX was reversed by cyclin B1. We also found that overexpression of cyclin B1 could significantly increase the sensitivity of MCF-7 cells to PTX by stimulating soluble polymerized tubulin. Overall, hypoxia decreases cyclin B1, which could in turn reverse hypoxia-induced decreasing chemosensitivity to PTX in breast cancer cell line MCF-7.

[Protective effects of mitochondrial ATP-sensitive potassium channel on A549 cell apoptosis induced by hyperoxia]

OBJECTIVE

To explore the protective effects of mitochondrial ATP-sensitive potassium channel opener diazoxide on hyperoxia-induced apoptosis of type II alveolar epithelial cells (A549 cells) and possible mechanisms.

METHODS

A549 cells were cultured in vitro and divided randomly into control, hyperoxia and diazoxide group. The hyperoxia group was exposed to a mixture of O2 (900 mL/L) and CO2 (50 mL/L) for 10 minutes, then cultured in a closed environment. The diazoxide group was pretreated with diazoxide of 100 μmol/L for 24 hrs before hyperxia induction. The cells were collected 12, 24 and 48 hrs after culture. The morphologic changes of A549 cells were observed under an inverted microscope. A549 cell apoptosis was detected by flow cytometry. The expression of Omi/HtrA2 in the endochylema of A549 cells was determined by immunohistochemistry.

RESULTS

A549 cells were damaged and the changes in morphology of the cells were serious in the hyperoxia group. The apoptosis rate of A549 cells and the expression of Omi/HtrA2 in the endochylema increased in the hyperoxia group compared with the control group (P<0.05). The growth and the morphology of A549 cells were greatly improved and the cell injuries were obviously alleviated in the diazoxide group. The expression of Omi/HtrA2 in the endochylema and the apoptosis rate of A549 cells were significantly reduced in the diazoxide group compared with the hyperoxia group (P<0.05).

CONCLUSIONS

Diazoxide as an opener of mitoKATP channel can reduce the expression of Omi/HtrA2 and the apoptosis rate of A549 cells, thus relieves the injury of A549 cells induced by hyperoxia.

[Effects of Ucf-101 on expression of Omi/HtrA2 in kidneys of postasphyxial neonatal rats]

OBJECTIVE

To investigate the expression of serine protease Omi/HtrA2 in kidneys of postasphyxial neonatal rats, and to study the effects of Ucf-101 on apoptosis and the expression of Omi/HtrA2 in these rats.

METHODS

Seventy-two neonatal Wistar rats of 7-10 days old were randomly divided into 3 groups: control, postasphyxial model, Ucf-101-treated postasphyxialThe postasphyxial model was established by normobaric asphyxiaExpression of Omi/HtrA2 was determined with streptavidin-peroxidase immunohistochemistry 2, 24 and 48 hrs after asphyxia. Terminal deoxynuleotidyl-mediated nick end labeling (TUNEL) was used to ascertain the apoptosis of renal cells.

RESULTS

Compared with the control group, OmiHtrA2 expression in renal cells began to increase 2 hrs after asphyxia and peaked at 24 hrs. The expression of Omi/HtrA2 in the Ucf-101-treated postasphyxial group was significantly lower than that in the postasphyxial model group (P<0.01). TUNEL-positive cells began to increase 2 hrs after asphyxia and peaked at 24 hrs in the postasphyxial model group when compared with the control group. The number of TUNEL-positive cells in the Ucf-101-treated postasphyxial group was significantly lower than that in the postasphyxial model group at all time points (P<0.01).

CONCLUSIONS

The expression of Omi/HtrA2 in kidneys is increased in postasphyxial neonatal rats. The increased Omi/HtrA2 expression may play an important role in the development of postasphyxial renal injury. Treatment with Ucf-101 can reduce the expression of Omi/HtrA2 in kidneys of postasphyxial neonatal rats and thus reduce renal tububar epithelial cell apoptosis.

Improving outcome of transplanted mesenchymal stem cells for ischemic heart disease

Mesenchymal stem cells (MSCs) transplantation has been proposed as a promising means for the repair and regeneration of heart cells in ischemia heart disease. However, advancement in stem cell therapy is hindered by the poor survival of implanted cells. Recently, many kinds of methods have been developed to prevent stem cells apoptosis and improve their therapeutic potential in the ischemia heart, including genetically modifying, retaining viability in vitro, suitable transplantation means, and preconditioning. Despite the great promise of these methods, there are still many problems to be solved in this field, including limited kinds of experimental animals, few clinical trials, and cell differentiation.

Clinical effective analysis of chemo-radiotherapy for esophageal carcinoma patients with dietary and lifestyle factors of high and low risk

AIM: To study the clinical effects of chemo-radiotherapy for esophageal carcinoma patients with dietary and lifestyle factors of high risk.

METHODS: In a nested case-control study, data for esophageal carcinoma potential determinants from a survey that conducted on 496 patients in Wanzhou district of Chongqing municipality was analyzed. The classification tree model was constructed using exhaustice chi-square automatic interactiong detection method. The clinical effects of chemo-radiotherapy for esophageal carcinoma patients were observed.

RESULTS: In 7 out of the 15 risk factors selected, water pollution and fast eating were the most important factors. Furthermore, esophageal carcinoma was more frequent among smokers and fast eaters in alcohol drinkers. There were more survival benefits for esophageal carcinoma patients with high risk dietary and lifestyle factors (the median survival time, 21 month) relative to low risk patients (14 month) followed by chemo-radiotherapy. Significant difference was found between two groups (t = 15.87, P < 0.01).

CONCLUSION: It is possible that water pollution, and poor dietary and lifestyle factors such as hot-temperature food items and fast eating, smoking and alcohol drinking were the main risk factors for esophageal carcinoma of Wanzhou region. Chemo-radiotherapy has more clinical benefits for esophageal carcinoma patients with diet habits and lifestyle factors of high risk.

Transforming growth factor-beta1 enhanced vascular endothelial growth factor synthesis in mesenchymal stem cells

Angiogenesis is essential for transplantation of mesenchymal stem cells (MSCs). Vascular endothelial growth factor (VEGF) is one of the most potent angiogenic factors identified to date. Elevated VEGF levels in MSCs correlate with the potential of MSCs transplantation. As an indirect angiogenic agent, transforming growth factor-beta1 (TGF-beta1) plays a pivotal role in the regulation of vasculogenesis and angiogenesis. However, the effect of TGF-beta1 on VEGF synthesis in MSCs is still unknown. Besides, the intracellular signaling mechanism by which TGF-beta1 stimulates this process remains poorly understood. In this article, we demonstrated that exposure of MSCs to TGF-beta1 stimulated the synthesis of VEGF. Meanwhile, TGF-beta1 stimulated the phosphorylation of Akt and extracellular signal-regulated kinase 1/2 (ERK1/2). Moreover, Ly 294002, a specific inhibitor of phosphatidylinositol-3-kinase (PI3K)/Akt significantly attenuated the VEGF synthesis stimulated by TGF-beta1. Additionally, U0126, a specific inhibitor of ERK1/2, also significantly attenuated the TGF-beta1-stimulated VEGF synthesis. These results indicated that TGF-beta1 enhanced VEGF synthesis in MSCs, and the Akt and ERK1/2 activation were involved in this process.

The roles of mesenchymal stem cells (MSCs) therapy in ischemic heart diseases

Growing cell-based myocardial therapies which could lead to successful myocardial repair attracts medical interest. Even more intriguing is the observation that MSCs appears to be a more potent material among kinds of stem cells for the transplantation, the mechanism for this benefit remains unclear. However, the therapeutic contribution of MSCs to myocardial repair can be caused by multiple factors including: direct differentiation into cardiac tissue including cardiomyocytes, smooth muscle cell, and vascular endothelial cells; secreting a variety of cytokines and growth factors that have paracrine activities; spontaneous cell fusion; and stimulating endogenous repair. In addition, MSCs possess local immunosuppressive properties, and MSCs mobilization is widely used clinically for transplantation. We will discusses the potential mechanisms of MSCs repair for ischemic heart diseases.

Yizhi capsule for vascular dementia

BACKGROUND

Vascular dementia (VD) is a syndrome or diagnosis that has different causes and clinical manifestations relating to several different vascular mechanisms and changes in the brain. Some traditional Chinese herbal medicines were developed for treating VD. DH: Yizhi capsule is one such herbal concoction which is reported to improve clinical symptoms significantly. The efficacy and adverse effects of Yizhi capsule need to be reviewed systematically and assessed critically to inform clinical practice and guide the continued search for new treatment regimens.

OBJECTIVES

To assess the effectiveness and possible adverse events of 'Yizhi capsule' in treating vascular dementia.

SEARCH STRATEGY

The Cochrane Dementia and Cognitive Improvement Group's Specialised Register was searched on 18 September 2006 using the terms yi-zhi, "yi zhi" and yizhi. This database contains trial references from major health care databases and ongoing trial database and is up to date. In addition the review authors searched a variety of Chinese databases.

SELECTION CRITERIA

Randomised, placebo controlled trials in which patients with vascular dementia were treated with 'Yizhi capsule' were included.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. We telephoned study authors for missing information as to whether treatment allocation was randomised and other methodological details.

MAIN RESULTS

No studies were found that met the inclusion criteria. We identified nine references to trials which included the term 'Yizhi capsule' in the description of the interventions. Two study authors were contacted by telephone and we discovered that the allocation methods they had used were not actually randomised. Four references were describing the same study. Three studies were excluded because 'positive drugs' were used as a control.

AUTHORS' CONCLUSIONS

There is no evidence from randomised controlled trials to support or proscribe against the use of 'Yizhi capsule' as a treatment for vascular dementia.

Stress-induced c-Jun-dependent Vitamin D receptor (VDR) activation dissects the non-classical VDR pathway from the classical VDR activity

Vitamin D receptor (VDR) is a ligand-dependent transcription factor that mediates vitamin D(3)-induced gene expression. Our previous work has established that stress MAPK signaling stimulates VDR expression (Qi, X., Pramank, R., Wang, J., Schultz, R. M., Maitra, R. K., Han, J., DeLuca, H. F., and Chen, G. (2002) J. Biol. Chem. 277, 25884-25892) and VDR inhibits cell death in response to p38 MAPK activation (Qi, X., Tang, J., Pramanik, R., Schultz, R. M., Shirasawa, S., Sasazuki, T., Han, J., and Chen, G. (2004) J. Biol. Chem. 279, 22138-22144). Here we show that c-Jun is essential for VDR expression and VDR in turn inhibits c-Jun-dependent cell death by non-classical mechanisms. In response to stress c-Jun is recruited to the Vdr promoter before VDR protein expression is induced. The necessary and sufficient role of c-Jun in VDR expression was established by the fact that c-Jun knock-out decreases VDR expression, whereas c-Jun restoration recovers its activity. Existence of the non-classical VDR pathway was suggested by a requirement of both c-Jun and VDR in stress-induced VDR activity and further demonstrated by VDR inhibiting c-Jun-dependent cell death independent of its classical transcriptional activity and independent of vitamin D(3). c-Jun is also required for vitamin D(3)-induced classical VDR transcriptional activity by a mechanism likely involving physical interactions between c-Jun and VDR proteins. These results together reveal a non-classical mechanism by which VDR acts as a c-Jun/AP-1 target gene to modify c-Jun activity in stress response through increased protein expression independent of classical transcriptional regulations.

[Depressive effect of tetrandrine on collagen synthesis in vascular smooth muscle cells]

AIM

To clarify whether collagen deposition and collagen synthesis are increased in renovascular hypertensive rats (RHR) and whether these are affected by treatment with tetrandrine (Tet).

METHODS

Collagen deposition was detected by electron microscope and evaluated by the amount of hydroxyproline in aorta of sham-operated rats (Sham), renovascular hypertensive rats (RHR), and Tet treated RHR. The aortic vascular smooth muscle cells (AVSMCs) were isolated and cultured. The collagen synthesis in cultured AVSMCs was detected by [3H]-proline incorporation.

RESULTS

The ultrastructure of aorta suggests that AVSMCs in RHR had been transferred from contractile phenotype to synthetic phenotype. Compared with sham-operated rats, the hydroxyproline content in aorta was increased by 36.6% in RHR, while it was reduced by 18.7% in Tet treated RHR (P < 0.01, vs RHR). Tet (0.1-10 mumol.L-1) treatment in vitro induced a concentration dependent depression [3H]-proline incorperation stimulated by NE or Ang II in AVSMCs from either Sham or RHR.

CONCLUSION

The depressive effects of tetrandrine on collagen synthesis and deposition in arteries may contribute to the regression of vascular remodeling.

Isolation and complete nucleotide sequence of a Chinese Sindbis-like virus

Infection with alphaviruses is common in the Chinese population. Here we report the isolation of a Sindbis-like virus from a pool of Anopheles mosquitoes collected in Xinjiang, China during an arbovirus survey. This virus, designated XJ-160, rapidly produced cytopathic effects on mosquito and hamster cells. In addition, it was lethal to neonatal mice if inoculated intracerebrally. Serologically, XJ-160 reacted with and was neutralized by an anti-Sindbis antibody. Anti-XJ-160 antibodies were found in several cohorts of Chinese subjects. The complete 11626-base nucleotide sequence of XJ-160 was determined. XJ-160 has diverged significantly from the prototype Sindbis virus, with an 18% difference in nucleotide sequence and an 8.6% difference in amino acids; there are 11 deletions and 2 insertions, involving 99 nucleotides in total. XJ-160 is most closely linked to Kyzylagach virus isolated in Azerbaijan. Both belong to the African/European genetic lineage of Sindbis virus, albeit more distantly related to other members.

Restraint stress changes heart sensitivity to arrhythmogenic drugs

AIM

To study the effects of acute restraint stress on ventricular electric stability (VES) and its mechanisms of action.

METHODS

VES was evaluated both in vivo and in vitro by the changes of arrhythmogenic responses to icv or ip aconitine in rats and iv BaCl2 or adrenaline in rabbits following restraint stress for different durations. Pretreatments and the assay of heart-specific enzymes were made.

RESULTS

The heart sensitivity to these drugs was promoted after stress for 2 h, but obtunded after stress for 8 h (the latency of ventricular arrhythmia to icv aconitine was shortened from 4.1 +/- 0.9 min in control rats to 2.9 +/- 0.9 min after stress for 2 h, P < 0.05; but prolonged to 9.3 +/- 3.8 min after stress for 8 h, P < 0.05). In Langendorff heart, the changes of VES induced by stress were similar to those in vivo, but to lesser degree. Pretreatment with adrenalectomy inhibited the descending phase of VES, while pretreatment with both aminophylline and vagotomy remarkably depressed the ascending phase at 8 h. In addition, the serum activities of lactate dehydrogenase (LDH), creatine kinase (CK), and aspartate aminotransferase and their isozymes, LDH1 and CK-MB, were elevated at 2 h, and rose continuously at 8 h.

CONCLUSION

Acute restraint stress causes biphasic changes of VES. The initial decrease of VES was related to adrenal catecholamine release, whereas the following increase of VES was ascribed to adaptive decrease of cAMP and vagal activation. The changes of VES did not always parallel the injury of heart.

Frequency-dependent depression of Vmax in K(+)-depolarized guinea pig papillary muscle by tetrandrine

The effect of tetrandrine (Tet), a calcium antagonist, on the maximal upstroke velocity (Vmax) of depolarization in K(+)-depolarized guinea pig papillary muscles was studied by standard microelectrode method with computer. The results showed that: (1) the resting block of Tet on Vmax was concentration dependent; (2) the drug (50 or 100 mumol.L-1) caused a marked frequency-dependent block of Vmax, which accounted for 65 +/- 8% of total block at a concentration of 100 mumol.L-1 and the pacing frequency of 0.3 Hz; (3) the recovery kinetics of Vmax could be characterized as a biexponential function, of which the second phase was prolonged by the drug; (4) compared with verapamil, nitrendipine, and diltiazem, the above-mentioned effects of Tet on Vmax were similar to those of diltiazem. These results suggest that Tet can block calcium channel in both frequency-dependent and frequency-independent manner, mainly the former.