Primary percutaneous coronary intervention in a COVID-19 patient with ST-segment elevation myocardial infarction after lung transplantation: a case report / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

We present an unusual case of a patient with bilateral-lung transplantation due to severe coronavirus disease 2019 (COVID-19), who subsequently suffered complications with acute myocardial infarction and underwent primary percutaneous coronary intervention (PCI).

Losartan's effects on the protein expression of the kidney of spontaneous hypertension rat / 中国应用生理学杂志

<p><b>AIM</b>To analyse the alterations of protein expression in the kidney of spontaneously hypertensive rat with losartan.</p><p><b>METHODS</b>The proteins of the kidney were isolated by two-dimensional gel electrophoresis. The protein spots with significant changes were selected for further identification by LC-MS/MS.</p><p><b>RESULTS</b>The number of average protein spots of two groups was 570 +/- 48 and 686 +/- 30 respectively. Compared with the SHR, 13 spots had changed significantly after treated with losartan. There were 5 protein spots detected only in SHR group, while 4 up-regulated and 4 down-regulated protein spots were detected in SHR-L group. These differentially expressed proteins were detected by mass spectrometry. 7 spots were identified. There were Heat shock protein (Hsp), Tubulin alpha-1 chain, Transthyretin precursor, Liver regeneration-related protein LRRG03, Ezrin-radixin-moesin binding phosphoprotein 50, Phosphoglycerate kinase 1 and Anionic trypsin I precursor.</p><p><b>CONCLUSION</b>The different protein spots expression may play important roles in Losartan's effective protection to hypertension rats renal tissue.</p>

Inhibitory effect of resveratrol on cardiac fibroblast proliferation induced by angiotensin II / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To observe the effect and mechanism of resveratrol on cardiac fibroblast (cFs) proliferation induced by angiotensin II (Ang II).</p><p><b>METHODS</b>The in vitro cFs proliferation model was established by stimulating cultured cFs of new born rats with Ang II by differential attachment method. Cell proliferation was measured by MTT assay, and the effect of resveratrol, L-NAME and ODQ on cell proliferation were observed respectively. Besides, the hypertrophic response of cFs was estimated by measuring expressions of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) mRNA, with the levels of ANP and BNP in culture medium determined by radioimmunoassay and ELISA respectively; and their mRNA expressions determined by reverse transcription polymerase chain reaction (RT-PCR). Level of nitric oxide (NO) in the culture medium was measured by Griess reagent; nitric oxide synthase (NOS) level by chemical colorimetric method; and cGMP by radioimmunoassay.</p><p><b>RESULTS</b>Resveratrol at the dose of 25-100 micromol/L inhibited cFs proliferation in a time and dose dependent manner, which could be partially blocked by pretreatment with L-NAME or ODQ. NO and cGMP levels increased, ANP, BNP levels and their mRNA expression lowered after resveratrol treatment.</p><p><b>CONCLUSION</b>Resveratrol in a definite concentration range could inhibit cFs proliferation and hypertrophic response induced by Ang II, up-regulating the signal pathway of NO and cGMP might be one of the acting paths of the inhibitory effects.</p>

Inhibitory effects of emodin on proliferation of rat vascular smooth muscle cell induced by angiotensin II / 中国中药杂志

<p><b>OBJECTIVE</b>To investigate the effects of emodin on the proliferation of cultured rat vascular smooth muscle cell (VSMC) induced by angiotensin II.</p><p><b>METHOD</b>VSMCs were cultured by explant method. Cell proliferation model was established by stimulation with Ang II. Cell proliferation was measured by MTT assay to observe the effects of emodin (10, 20, 40 and 80 micromol x L(-1)) and N(G)-nitro-L-arginine methyl ester (L-NAME, 100 micromol x L(-1)) on VSMC proliferation induced by Ang II. The expression of PCNA was measured by immunohistochemical staining. Nitric oxide (NO) level was measured by Griess reagent. Nitric oxide synthase (NOS) and inducible nitric oxide synthase (iNOS) levels were detected by chemical colorimetric method. mRNA expression of iNOS was measured by reverse transcription polymerase chain reaction (RT-PCR).</p><p><b>RESULT</b>Emodin at the doses range from 10 to 80 mol x L(-1) inhibited cell proliferation in a dose and time-dependent manner. The inhibitory effects were partly blocked by 100 mol x L(-1) of L-NAME. Emodin markedly decreased the expression of PCNA in VSMC, increased NO, NOS and iNOS levels, and increased iNOS mRNA expression in VSMC.</p><p><b>CONCLUSION</b>Emodin could inhibite VSMCs proliferation induced by Ang II. Inhibiting the expression of PCNA, increasing the NO secretion and upregulating the iNOS gene expression might be associated with the inhibitory effects.</p>

PPAR alpha activator fenofibrate regressed left ventricular hypertrophy and increased myocardium PPAR alpha expression in spontaneously hypertensive rats / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the effect of PPAR alpha activator fenofibrate on left ventricular hypertrophy and myocardium PPAR alpha (peroxisome proliferator-activated receptor-alpha) expression in spontaneously hypertensive rats (SHR).</p><p><b>METHODS</b>Sixteen nine-week-old male spontaneously hypertensive rats were randomly divided into two groups: SHR received fenofibrate 100 mg x kg(-1) x d(-1) by oral gavage once daily for 8 weeks (SHR-F, n=8), and SHR received vechile (0.9 % saline) acted as controls (SHR, n=8). Age-matched Wistar-kyoto rats received vehicle for 8 weeks were served as negative controls (WKY, n=8). Systolic blood pressure was measured at the beginning, 2, 4, and 8 weeks of the experiment. At the end of the experiment, plasma BNP (brain natriuretic peptide)and lipid levels were measured. Left ventricular hypertrophy was accessed by pathological analysis. The expression of PPAR alpha and nuclear factor-kappa B (NF-kappa B p65) were investigated by the method of Western blotting.</p><p><b>RESULT</b>Compared with SHR group, systolic blood pressure was slightly lowered in SHR-F group, but it didn't reach significant level(p>0.05). Fenofibrate administration lowered plasma BNP in SHR-F group (P<0.01). There were not much difference of plasma lipid levels between SHR-F and SHR group. Left ventricular mass index (assessed by left ventricular weight/body weight, g x kg(-1)), transdiameter of cardiomyocyte (TDM), cardiomyocyte area (CA), collagen volume fraction (CVF), and perivascular circumferential area (PVCA) decreased significantly in SHR-F group (P<0.05, P<0.01). The myocardium PPAR alpha expression increased significantly (P<0.01), and NF-kappa B p65 expression decreased significantly (P<0.01) in SHR-F group.</p><p><b>CONCLUSION</b>PPAR alpha activator fenofibrate can regress left ventricular hypertrophy and increase myocardium PPAR alpha expression in spontaneously hypertensive rats, which is perhaps independent of its lipid-lowering activity.</p>

Effects of angiotensin converting enzyme inhibitor on the expression of angiotensin converting enzyme 2 in atrium of patients with atrial fibrillation / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the expression of angiotensin converting enzyme 2 (ACE2) and the changes treated with angiotensin converting enzyme inhibitor (ACEI), and its signal transduction pathway.</p><p><b>METHODS</b>Atrial tissues were obtained from 47 patients with RHD undergoing cardiac surgery. The mRNA of ACE2 and ACE were semi-qualified by RT-PCR and normalized to the gene beta-actin. Western blot analysis was employed to examine the expressions of ACE2, ACE, ERK1/2 and phosphorylated ERK (pERK1/2). The atrial tissue angiotensin II (Ang II) content was determined by radioimmunoassay detection.</p><p><b>RESULTS</b>The expression of ACE2 was significantly decreased (P < 0.05), the expression of ACE and pERK1/2 were significantly increased (P < 0.05), and the level of atrial tissue Ang II was significantly increased in patients with chronic atrial fibrillation group (CAF) compared with sinus rhythm group (SR) (P < 0.05). Compared with CAF patients treated without ACEI, the expression of ACE2 significantly increased (P < 0.01), and the relative activity of ERK1/2 significantly decreased (P < 0.05), whereas the expression of ACE and the level of atrial tissue Ang II remained unchanged in CAF patients treated with ACEI.</p><p><b>CONCLUSIONS</b>The study suggested that the dysequilibrium of ACE/ACE2 might play an important role in the process of atrial fibrillation, which may be related to the activation of ERK1/2 pathway. The clinical effect of long-term treatment of ACEI maybe associated with elevated ACE2 expression but not ACE expression.</p>

Proteomic analysis of the serum in patients with idiopathic pulmonary arterial hypertension / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Idiopathic pulmonary arterial hypertension (IPAH) is a rare disease of unknown etiology. The exact pathogenesis of pulmonary arterial hypertension is still not well known. In the past decades, many protein molecules have been found to be involved in the development of IPAH. With proteomic techniques, profiling of human plasma proteome becomes more feasible in searching for disease-related markers. In present study, we showed the protein expression profiles of the serum of IPAH and healthy controls after depleting a few high-abundant proteins in serum. Thirteen spots had changed significantly in IPAH compared with healthy controls and were identified by LC-MS/MS. Alpha-1-antitrypsin and vitronectin were down-regulated in IPAH and may be valuable candidates for further explorations of their roles in the development of IPAH.

A novel splice mutation of HERG in a Chinese family with long QT syndrome / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Congenital long QT syndrome (LQTS) is a genetically heterogeneous disease in which six ion-channel genes have been identified. The phenotype-genotype relationships of the HERG (human ether-a-go-go-related gene) mutations are not fully understood. The objective of this study is to identify the underlying genetic basis of a Chinese family with LQTS and to characterize the clinical manifestations properties of the mutation. Single strand conformation polymorphism (SSCP) analyses were conducted on DNA fragments amplified by polymerase chain reaction from five LQT-related genes. Aberrant conformers were analyzed by DNA sequencing. A novel splice mutation in C-terminus of HERG was identified in this Chinese LQTS family, leading to the deletion of 11-bp at the acceptor splice site of Exon9 [Exon9 IVS del (-12-->-2)]. The mutation might affect, through deficient splicing, the putative cyclic nucleotide binding domain (CNBD) of the HERG K(+) channel. This mutation resulted in a mildly affected phenotype. Only the proband had a history of syncopes, while the other three individuals with long QT interval had no symptoms. Two other mutation carriers displayed normal phenotype. No sudden death occurred in the family. The 4 affected individuals and the two silent mutation carriers were all heterozygous for the mutation. It is the first splice mutation of HERG reported in Chinese LQTS families. Clinical data suggest that the CNBD mutation may be less malignant than mutations occurring in the pore region and be partially dominant over wild-type function.

Changes of endothelial progenitor cells from peripheral blood in patients with coronary heart diseases / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate alterations of endothelial progenitor cells (EPCs) from peripheral blood in patients with coronary heart diseases.</p><p><b>METHODS</b>Twenty patients with coronary heart diseases (CHD) and 20 matched control subjects were included in the study. Total mononuclear cells (MNCs) were isolated from peripheral blood by Ficoll density gradient centrifugation, and then the cells were plated on fibronectin-coated culture dishes. After cultured for 7 days, attached cells were cytochemically analyzed. EPCs were characterized as adherent cells double positive for DiLDL-uptake and lectin-binding by laser scanning confocal microscope with direct fluorescent staining. EPCs proliferation and migration were measured by MTT assay and modified Boyden chamber assay, respectively. EPCs adhesion assay was performed by replating on fibronectin-coated dishes, then adherent cells were counted.</p><p><b>RESULTS</b>The number of EPCs was significantly reduced in patients with CHD compared with that of age-matched control subjects (31.8+/-7.7 compared with 59.5 +/-10.6 EPCs/x 200 field; P<0.05). In addition, the functional activity of EPCs such as proliferation, migration and adhesive capacity was also impaired in patients with CHD.</p><p><b>CONCLUSION</b>EPCs number and functional activity are significantly decreased in patients with CHD.</p>

Single nucleotide polymorphism in SCN5A and the distribution in Chinese Han ethnic group / 生理学报

Mutations in voltage-gated sodium channel type (SCN5A) may evoke severe, life-threatening disturbances in cardiac rhythm, including long QT syndrome, idiopathic ventricular fibrillation (Brugada Syndrome), and isolated cardiac conduction disease. There is increasing awareness of the role of common polymorphisms in altering gene function and in susceptibility to diseases. The aim of the present study was to investigate single nucleotide polymorphism (SNP) in SCN5A gene and the distribution of these identified SNPs in Chinese Han nationality. SCN5A gene was sequenced by fluorescent labeling automatic sequencing method in 120 unrelated samples from Han nationality in South China. Allele frequency distribution was tested by Hardy-Weinberg equilibrium. The results showed that a total of 5 SNPs were identified in SCN5A gene, including three SNPs in code region, one SNP in regulatory region and the other in intron 23 adjacent to donor splicing site. The distribution of the SNPs in SCN5A gene was uneven. These allele frequencies in Han population of South China were as follows: G87A (A29A) 27.5%, A1673G (H588R) 10.4%, 4245+82A>G 32.8%, C5457T (D1819D) 41.3% and G6174A 44.9% respectively. The SNPs G87A (A29A), 4245+82A>G and G6174A were reported for the first time. There was no significant difference in the allele frequency of A1673G (H558R) within different ethical populations (P>0.05). C5457T (D1819D) allele frequency of Han population in South China was similar to that observed in Japanese (P>0.5), but higher than that in American (p<0.005). There was no significant difference in the distribution of the SNPs between male group and female group (all p>0.05). S1102Y and other 10 SNPs identified in other ethnic populations have not been detected in Chinese Han population. The allele distribution of SNPs was in good unity with the Hardy-Weinberg equilibrium. It is suggested that the SNP distribution of SCN5A gene varies within different nationalities. These data will be of use for genetic association studies of acquired arrythmias and investigation of sensitivity to drug therapy.

Single nucleotide polymorphisms of the SCN5A gene in Han Chinese and their relation with Brugada syndrome / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Mutations in the cardiac sodium channel gene (SCN5A) may lead to a broad spectrum of familial arrhythmias, including long QT syndrome (LQTS), idiopathic ventricular fibrillation (IVF), and isolated cardiac conduction diseases. Recent studies have shown that polymorphisms in the SCN5A gene also play an important role in the manifestation of disorders involving cardiac excitability. In this study, we investigated the polymorphisms of the SCN5A gene in Han Chinese and its relation to Brugada syndrome (BS).</p><p><b>METHODS</b>Genomic DNA was isolated from 120 unrelated healthy volunteers and 48 unrelated Brugada syndrome patients by means of standard procedures. All exons including the putative splicing sites of the SCN5A gene were amplified by PCR and sequenced directly or after subcloning using an ABI Prism 377 DNA sequencer.</p><p><b>RESULTS</b>A total of 5 single nucleotide polymorphisms (SNPs) were identified in the Han Chinese population, including 3 novel ones: G87A(A29A), 4245 + 82A > G, and G6174A. The allele frequencies of each SNP in the Han Chinese population were as follows: G87A (A29A) 27.5%, A1673G (H558R) 10.4%, 4245 + 82A > G 32.8%, C5457T (D1819D) 41.3%, and G6174A 44.9%. S1102Y and 10 other SNPs identified in other ethnic populations were not detected in this study. There was no significant difference in the allele frequency of A1673G (H558R) between different ethnic populations (all P > 0.5). On the other hand, the allele frequency of C5457T (D1819D) among Han Chinese was similar to its frequency among Japanese (P > 0.5), but higher than that among Americans (P < 0.005). The allele G1673 (R558) was over-represented in BS patients compared to controls (P < 0.005), but there was no significant difference in genotype frequencies at this locus. There were also no differences in either the allele or genotype frequencies of the 4 other identified SNPs when comparing BS patients with healthy controls.</p><p><b>CONCLUSIONS</b>The distribution of SCN5A SNPs may vary between different ethnicities. The polymorphism of A1673G might be associated with BS and may contribute to a susceptibility to BS in Han Chinese.</p>

Effects of puerarin on number and activity of endothelial progenitor cells from peripheral blood / 中国中药杂志

<p><b>OBJECTIVE</b>To investigate whether puerarin can augment endothelial progenitor cells (EPCs) numbers, promote EPC proliferation, migration and adhesion.</p><p><b>METHOD</b>Total mononuclear cells (MNCs) were isolated from peripheral blood by Ficoll density gradient centrifugation, and then the cells were plated on fibronectin-coated culture dishes. After 7 days culture, attached cells were stimulated with puerarin (to make a series of final concentrations: 0. 1, 0.5, 1, 3 mmol x L(-1)) or vehicle control for the respective time points (6, 12, 24, 48 h). EPCs were characterized as adherent cells double positive for DiLDL-uptake and lectin binding by direct fluorescent staining under a laser scanning confocal microscope. EPCs proliferation, migration and in vitro vasculogenesis activity were assayed with MT assay, modified Boyden chamber assay and in vitro vasculogenesis kit, respectively. EPCs adhesion assay was performed by replating those on fibronectin-coated dishes, then adherent cells were counted.</p><p><b>RESULT</b>Incubation of isolated human MNCs with puerarin dose increased the number of EPCs, maximum at 3 mmol x L(-1), 24 hours (approximately 1-fold increase, P < 0.01). In addition, puerarin also promoted EPC proliferative, migratory, adhesive and in vitro vasculogenesis capacity.</p><p><b>CONCLUSION</b>Puerarin can augment the number of EPCs with enhanced functional activity.</p>

Identification of a novel mutation at the point of low density lipoprotein receptor gene from a subject with familial hypercholesterolemia / 生理学报

Family hypercholesterolemia (FH) is a genetic disorder caused by mutation in the low density lipoprotein receptor (LDLR) gene. It is characterized by a high concentration of low density lipoprotein (LDL), which frequently gives rise to tendon xanthenes and premature coronary artery disease. We studied a FH family ,which was diagnosed by clinical features and blood lipid tests. The Total cholesterol level of the family was 19.05 mmol/L and the LDL level was 17.06 mmol/L in the proband homozygous FH subjects, while the total cholesterol was 7.96 mmol/L and LDL was 5.55 mmol/L in the heterozygous FH subjects. DNA segments amplified with PCR were sequenced in heterozygous and homozygous FH patients. Two novel identical mutation alleles of GAG683GCG, which caused an amino acid change from Glu to Ala, were detected in Exon4 of LDL receptor gene in homozygous proband. DNA sequencing revealed that the proband's parents were heterozygotes with the same mutational alleles as the proband. These results are in coincidence with the clinical diagnoses. Moreover Epstein-Barr virus transformed lymphocytes (EBV-Ls) were derived by routine virus infection transforming protocol. The cells bounded with the fluorescently conjugated LDL were measured by fluorescence flow cytometry. The ratios of functional LDLR in EBV-Ls originated from homozygous FH, heterozygous FH and normal control were 7.02%, 62.64% and 84.69%, respectively. As a result, the homozygous FH patient's LDLR had 8.29% and the heterozygous FH patient's LDLR had 73.96% of the activity of the control. It is apparent that LDL receptor activity of homozygous FH subject is significantly lower than normal control. The data from fluorescence flow cytometry analysis of EBV-Ls strongly support the clinical diagnoses and the results of DNA sequencing. In accordance with the updated version of UMD-LDLR, the mutant GAG683GCG in Exon4 of LDLR gene which we have identified is a novel mutation of the LDLR gene in human with hypercholesterolemia.

Statins contribute to enhancement of the number and the function of endothelial progenitor cells from peripheral blood / 生理学报

The aim of the present study was to investigate whether fluvastatin augments the number of endothelial progenitor cells (EPCs), and promotes EPCs proliferation, migration and adhesion. Total mononuclear cells (MNCs) were isolated from peripheral blood by Ficoll density gradient centrifugation. The cells were then plated on fibronectin-coated culture dishes. After being cultured for 7 d, the attached cells were stimulated with fluvastatin (final concentrations: 0.01, 0.1, 1, 10 micromol/L), simvastatin (1 micromol/L) or a vehicle for the respective time points (6, 12, 24 and 48 h). EPCs were characterized as adherent cells double positive for DiLDL-uptake and lectin binding by direct fluorescent staining under a laser scanning confocal microscope. EPCs were further documented by demonstrating the expression of KDR, VEGFR-2 and AC133 with flow cytometry. EPCs proliferation, migration and in vitro vasculogenesis activity were assayed by MTT assay, modified Boyden chamber assay and in vitro vasculogenesis kit, respectively. EPCs adhesion assay was performed by replating it on fibronectin-coated dishes, and the adherent cells were then counted. In addition, we also studied EPCs culture assay of peripheral blood from fluvastatin-treated animals in vivo. Incubation of isolated human MNCs with fluvastatin dose- and time-dependently increased the number of EPCs, while reached the maximum 24 h after the administration at 1 micromol/L, (2.5-fold increase, P<0.05). Moreover, treatment of rats with fluvastatins elevated the number of EPCs (3-fold increase, P<0.05), thus extending the in vitro data. In addition, fluvastatin also promoted EPC proliferation, migration, adhesion and in vitro vasculogenesis in a concentration-dependent manner. The effects of fluvastatin on EPCs were compared with those of simvastatin at the same concentration (1 micromol/L), with a result of no statistical difference. The results of the present study define a novel mechanism of the action of statins: the augmentation of EPCs with enhanced functional activity.

Effects of Ginkgo biloba extract on number and activity of endothelial progenitor cells from peripheral blood / 药学学报

<p><b>AIM</b>To investigate whether Ginkgo biloba extract can augment endothelial progenitor cell (EPC) number, and promote EPC proliferation, migration and adhesion.</p><p><b>METHODS</b>Total mononuclear cells (MNCs) were isolated from peripheral blood by Ficoll density gradient centrifugation, and then the cells were plated on fibronectin-coated culture dishes. After 7 days of culture, attached cells were stimulated with Ginkgo biloba extract (10, 25 and 50 mg x L(-1)) or vehicle control for the respective time points (6, 12, 24 and 48 h). EPC were characterized as adherent cells double positive for DiLDL-uptake and lectin binding by direct fluorescent staining under a laser scanning confocal microscope. EPC were further documented by demonstrating the expression of CD34, VEGFR-2 and AC133 with flow cytometry. EPC proliferation, migration and in vitro vasculogenesis activity were assayed with MTT assay, modified Boyden chamber assay and in vitro vasculogenesis kit, respectively. EPCs adhesion assay was performed by replating MNCs on fibronectin-coated dishes, and then counting adherent cells.</p><p><b>RESULTS</b>Incubation of isolated human MNCs with Ginkgo biloba extract increased the number of EPC, maximum at 25 mg x L(-1), 24 hours (approximately 1-fold increase, P < 0.01). In addition, Ginkgo biloba extract promotes EPC proliferative, migratory, adhesive and in vitro vasculogenesis capacity.</p><p><b>CONCLUSION</b>Ginkgo biloba may promote EPC augmentation and enhance its functional activity.</p>

Dependence of ventricular wallstress-induced refractoriness changes on pacing cycle lengths and its mechanism / 生理学报

The aim of this article was to investigate the dependence of ventricular wallstress-induced refractoriness changes on pacing cycle lengths and its mechanism in anaesthetized rabbits. The rabbit heart preparation was used. The left ventricular afterload was increased by partially clipping the root of the ascending aorta. The changes in effective refractory periods (ERP) induced by the left ventricular afterload rising were examined at different pacing cycle lengths (1000, 500, 300 and 200 ms). In addition, the effect of streptomycin on these changes was also observed. The results are as follows: (1) The rising of left ventricular afterload led to marked changes in ERP at rapidly pacing cycle lengths (300 ms, 21+/-5 ms, 17.0%; 200 ms, 19+/-3 ms, 18.8%. P<0.01) than at slow ones (1000 ms, 3+/-2 ms, 1.5%; 500 ms, 7+/-3 ms, 4.0%. P>0.05); (2) Streptomycin inhibited the changes caused by the left ventricular afterload rising at pacing cycle lengths 300 ms and 200 ms (P>0.05). It is suggested that ventricular wallstress-induced refractoriness changes are pacing cycle length-dependent, and the effect of streptomycin appears to be consistent with the inhibition of stretch-activated ion channels.

Effect of tetradrine on electrophysilogic changes caused by rising of left ventricular preload in guinea pigs / 中国中药杂志

<p><b>OBJECTIVE</b>To investigate the changes of guinea pig heart electrophysiological properties caused by increasing left ventricular preload, and to assess the effects of tetradrine on these changes.</p><p><b>METHOD</b>Working model preparation of guinea pig hearts in vitro was used, and the preload of left ventricle was increased by adjusting the prefusion pressure of left atria. The changes of heart electrophysiologic parameters including monophasic action potential duration (MAPD90), monophasic action potential amplitude (MAPA), effective refractory period (ERP) and ventricular fibrillation threshold (VFT) were observed before and after altering the preload of left ventricle, and compared in the absence and presence of tetradrine, streptomycin or verapamil.</p><p><b>RESULT</b>The rising of left ventricular preload led to shortening of MAPD90, ERP, and to descent of MAPA, VFT (all P<0.01). Both Tetradrine and streptomycin inhibited these changes of heart electrophysiologic parameters caused by elevation of left ventricular afterload (all P<0.01). In contrast, verapamil had no effects on the preload-related electrophysiological changes (all P>0.05).</p><p><b>CONCLUSION</b>Electrophysiologic changes caused by increasing left ventricular preload may be inhibited by tetrandrine, through inhibition of stretch-activated ion channels.</p>

Adenosine protects cardiomyocytes from hypoxia/reoxygenation injury / 生理学报

The aim of this study was to investigate the protective effect of adenosine (ADO) on cardiomyocytes following hypoxia/reoxygenation (H/R) and its molecular mechanism. Primary cultured cardiomyocytes of neonatal rats were divided into two groups, namely H/R (control) and ADO (1.0 micromol/L) groups. The morphologic changes in cardiomyocytes were observed under an inverted phase-contrast microscope. The following parameters of the two groups were determined: lactate dehydrogenase (LDH) activity, intracellular calcium concentration and malondialdehyde (MDA) content. Tumor necrotic factor (TNF-alpha) assay was performed using an ELISA kit and NF-kappaB in the nucleus was analyzed by electrophoretic mobility shift assay (EMSA). The results are as follows: (1) after H/R injury, cardiomyocytes contracted, tending to get round in shape and its pseudopods decreased, while marked morphological changes were not observed in ADO group; (2) LDH leakage maintained at a lower level in ADO group than that in the control group during H/R (both P<0.01); (3) ADO significantly reduced the concentration of calcium in cells and prevented calcium overload during H/R (both P<0.01); (4) ADO markedly reduced the content of MDA during H/R (both P<0.01); (5) ADO inhibited the production of TNF-alpha during H/R (both P<0.01); and (6) ADO down-regulated NF-kappaB binding activity of cardiomyocytes during H/R (both P<0.01) The results suggest that (1) exogenous ADO attenuates H/R injury of cultured cardiomyocytes; (2) exogenous ADO inhibits the production of TNF-alpha after H/R injury; (3) exogenous ADO prevents the activation of NF-kappaB, which may be the molecular mechanism of down-regulation of TNF-alpha expression.