[Identification and evaluation on methods with upstream flank sequences of CRISPR1, regarding Escherichia coli and Shigella]

Objective: To analyze the effect of the identification and evaluation of Escherichia (E.) coli and Shigella, based on the upstream flanking sequences of CRISPR1. Methods: Both CRISPR and cas sequences were obtained through the BLAST with repeating sequences against the publicly complete genome in GenBank that related to E. coli and Shigella. Clustal X was used to perform multi-sequences alignment of the flanking sequences. PCR method was used to amplify the upstream flanking sequences of CRISPR1 in order to appraise the effect of identification and evaluation of upstream flanking sequences on E. coli and Shigella, which were based on the upstream flanking sequences of CRISPR1. Results: The results showed that 73.4% of the strains containing the I-E CRISPR/Cas that belonged to the phylogroups A, B1, D while 8.4% strains carried the I-F CRISPR/Cas. Another 17.2% of the strains owned CRISPR3-4 (non-CRISPR/Cas) only belonged to the phylogroups B2. All the Shigella strains carried I-E CRISPR/Cas. More than 99% of similarity the CRISPR1 upstream-flanking sequences was seen in E. coli (except B2) and Shigella and E. coli (B2). Both sensitivity and specificity were greater than 91% after PCR amplification in the region to identify the E.coli and Shigella. Conclusion: The upstream of CRISPR1 could achieve a preliminary identification effect on E.coli and Shigella.

The pharmacological research of Tek-1 relevance to anti-neuroinflammation, a candidate compound based on Telmisartan

In this paper, BV-2 mouse small glial cell inflammation model induced by LPS is established. The experiment used 0.1–10 μM of telmisartan and Tek-1 to incubate with small glial cell and used telmisartan and Tek-1 to incubate with PPAR gamma special heterosexual antagonistic anti-agent GW9662. The article used ELISA method to dectect TNF-a effect on small glial cell for telmisartan and Tek-1. The article used real-time quantitative PCR method to dectect mRNA level expression effect of CD11b, CD16 and iNOS on small glial cell for telmisartan and Tek-1 and used Western Blot method to dectect MAPKs signal pathway and NF-κb signal turned guide pathway effect on small glial cell for telmisartan and Tek-1. Results show that Tek-1 had high affinity with AT1 receptor and inhibited intracellular calcium ion activation which can be for the AT1 receptor antagonists. Meanwhile, Tek-1 can partially activate PPAR gamma compared with full agonists of rosiglitazone.

[Mechanism of drug-induced torsade de pointes: an experimental study in dogs]

OBJECTIVE

To investigate the mechanism of drug-induced torsade de pointes (Tdp) in dogs.

METHODS

In arterially perfused canine left ventricular wedge preparations, the action potential duration (APD) of the endocardial (Endo), midmyocardial (M) and epicardial (Epi) myocytes, and transmural electrocardiogram (ECG) were recorded simultaneously. The effects of different concentrations of D-Sotalol on APD, transmural dispersion of repolarization (TDR), early after depolarization (EAD) and Tdp were observed.

RESULTS

D-Sotalol prolonged APD of the Endo, M and Epi cells in a concentration-dependent manner from 0-100 µmol/L, and increased TDR due to a preferential APD prolongation of the M cells relative to Epi and Endo cells. The application of D-Sotalol elicited EAD, R on T ventricular premature beats, transmural reentry and Tdp in the M cells.

CONCLUSION

EAD and R on T ventricular premature beats induced by D-Sotalol in M cells triggers Tdp, which is maintained by TDR increment and transmural reentry.

[Eukaryotic expression vector pcDNA3-HERG transfection inhibits angiotensin II induced neonatal rabbit ventricular myocyte hypertrophy in vitro]

OBJECTIVE

To explore the effects of eukaryotic expression vector pcDNA3-HERG transfection on angiotensin II (Ang II) induced myocyte hypertrophy in cultured neonatal rabbit ventricular myocytes.

METHODS

Neonatal rabbit ventricular myocytes and eukaryotic expression vector pcDNA3-HERG transfected ventricular myocytes were cultured in Dulbecco's-modified Eagle medium (DMEM), containing 1% fetal bovine serum (FBS) for 6 h, then stimulated with Ang II (10(-7) mol/L) for 48 h. Control ventricular myocytes were cultured in Dulbecco's-modified Eagle medium (DMEM), containing 1% fetal bovine serum (FBS) for 54 h. At 6 and 54 h, myocyte hypertrophic parameters including myocyte volume, total protein content and membrane capacitance, action potential duration (APD) and Calcineurin (CaN) activity were measured.

RESULTS

Compared to control myocytes, APD at 90% repolarization (APD(90)) was prolonged by 19.8% (P < 0.01), without signs of myocyte hypertrophy at 6 h post Ang II stimulation, APD(90) was prolonged by 22.1% (P < 0.01), myocyte volume, total protein content and membrane capacitance and CaN activity were significantly increased by 40.4%, 40.4%, 38.2% and 114.7% respectively (all P < 0.01) at 48 h after Ang II stimulation. HERG gene transfection upregulated I(HERG) tail current (3.6-fold higher than I(Kr)-rapidly activating delayed rectifier potassium current, P < 0.01). HERG gene transfection also accelerated and repolarization and a shortened APD(90) and inhibited myocyte hypertrophy and CaN activation induced by Ang II.

CONCLUSIONS

Ang II induced prolongation of APD(90) is directly associated with myocyte hypertrophy by increasing the Ca(2+) influx and resulting in the increment of intracellular Ca(2+) and activation of CaN reaction pathway.

[Bone marrow stem cell mobilization to the peripheral blood and tumor necrosis factor-alpha expression in ischemic myocardium in rabbit models of hibernating myocardium]

OBJECTIVE

To investigate the changes in peripheral blood bone marrow stem cells and tumor necrosis factor-alpha gene expression in the ischemic myocardium in rabbit models of hibernating myocardium.

METHODS

Twenty-four male Japanese white rabbits were randomized into 4 groups, including a sham-operated group and 3 model groups with hibernating myocardium induced by partial ligation of the left anterior descending coronary artery. The percentage of CD34-positive cells in the peripheral blood was evaluated by flow cytometry, and TNF-alpha mRNA expression in the ischemic myocardium was determined by real-time RT-PCR in the 3 model groups (at 3, 7, or 28 days after the operation) and in the sham-operated group.

RESULTS

In rabbits with partial ligation of the left anterior descending coronary artery, the percentage of CD34-positive cells in the peripheral blood and myocardial TNF-alpha mRNA expression were significantly increased at 3 and 7 days after the operation in comparison with those in the sham-operated group and those at 28 days postoperatively (P<0.01). No significant differences were found in the percentage of CD34 positive cells or myocardial TNF-alpha mRNA expression between the sham-operated group and the rabbits 28 days after the coronary artery ligation (P>0.05).

CONCLUSION

Bone marrow stem cell can be mobilized into the peripheral blood in rabbit hibernating myocardium model possibly by increasing TNF-alpha gene expression in the ischemic myocardium.

[Identification of a novel KCNH2 mutation in a family with congenital long QT syndrome and prediction of the secondary structure of its encoding protein]

OBJECTIVE

To identify the gene mutation in a Chinese family with congenital long QT syndrome (LQTS) and predict the changes of the secondary structure of the protein.

METHODS

Polymerase chain reaction and DNA sequencing were used to screen for KCNH2 mutation in the proband. After the mutation was identified, KCNH2 gene of the family members was screened by multiplex PCR with site-specific primers. Network analysis software was used to predict the secondary structure of the KCNH2 protein.

RESULTS

A novel heterozygous missense mutation of F463L(GenBank accession no.EU218526) located at the transmembrane domain S2 of KCNH2 was detected. The mutation did not result in the change of the transmembrane domain, but altered the hydrophobicity and secondary structure of the protein.

CONCLUSION

The novel mutation identified in this study has enriched the GenBank data of ion channel gene mutation in LQTS. The changes of the secondary structure caused by the gene mutation were analyzed by Mfold and TMHMM software, which may help to understand LQTS.

Modified classic risk factors for coronary artery disease in Chinese Han population

OBJECTIVE

To investigate the levels of cardiovascular disease risk factors and their relations to clinical phenotype associated with coronary artery disease (CAD).

METHODS

The subjects were recruited from five independent cardiovascular centers. Coronary angiography was employed to define the CAD with stenosis in each major vessel > or = 70% and control with stenosis < 10% in every lesion. The classic risk factors including family history, body mass index, smoking habits, hypertension, diabetes mellitus, and serum lipid levels were surveyed according to established criteria. Associations between risk levels and clinical phenotypes were assessed by case control and correlation analysis.

RESULTS

A total of 762 individuals were collected, including 481 men and 281 women, aged from 17 to 81 (mean 60 +/- 10) years. The patients with CAD accounted for 55.5% of all participants, and controls 44.5%, respectively. Compared with the pattern in published data, our study showed that mean serum high density lipoprotein cholesterol (HDL-C) level was significantly lower (P < 0.001) and triglycerides was significantly higher (P < 0.001), while total cholesterol (TC) and low density lipoprotein cholesterol levels were comparative (both P > 0.05). The prevalence of low HDL-C (< 40 g/L) and hypertriglyceridemia (> 150 g/L) were 27.2% and 41.4%, respectively. Mean serum levels of HDL-C and apolipoprotein A1 were significantly higher in female subjects than in male (P < 0.001). Lower HDL-C functioned as an independent risk factor for CAD only in men (RR = 2.8, 95% CI: 1.5-4. 2, P < 0.001), yet increased non-HDL cholesterol combined with diabetes mellitus and obesity seemed to play a key role in the development of CAD in women. Similarity in risk association with CAD was found for hypertension and TC/HDL ratio in male and female subjects, while family history had no relationship with the presence of CAD.

CONCLUSION

It is remarkable that emphasis of intervention in future should be given on the prevalent low serum HDL-C and its strong risk correlation with the presence of CAD in male subjects of Chinese Han population.

[Effect of short-term intensive treatment with insulin pump on beta cell function and the mechanism of oxidative stress in newly diagnosed type 2 diabetic patients]

OBJECTIVE

To investigate the effect of short-term intensive treatment with insulin pump on beta cell function and the mechanism of oxidative stress in newly diagnosed type 2 diabetic patients.

METHODS

Totally 120 newly diagnosed type 2 diabetic patients were treated with insulin pump for 2 weeks. The levels of fasting plasma glucose (FPG), 2-hour postprandial blood glucose (2hPG), homeostatic model assessment of the insulin secretion index and insulin resistance index (HOMA-beta and HOMAIR, respectively), blood malondialdehyde (MDA) and superoxide dismutase (SOD) were measured before and after insulin pump treatment.

RESULTS

After insulin pump treatment, FPG, 2hPG, HOMAIR and blood MDA were significantly decreased (P<0.01), while HOMA-beta and blood SOD were significantly increased (P<0.01).

CONCLUSION

Short-term intensive treatment with insulin pump can effectively improve beta cell function probably by decreasing oxidative stress in newly diagnosed type 2 diabetic patients.

[Functional expression of congenital long QT syndrome related HERG mutation A561V in vitro]

OBJECTIVE

To investigate the functional expression of HERG mutation A561V detected in a Chinese congenital long QT syndrome family.

METHODS

The mutation gene A561V was cloned into eukaryotic expressive vector pcDNA3 by quick site-directed mutagenesis PCR and restriction enzymes. The wild-type HERG, heterozygous type HERG and HERG mutation A561V were respectively cotransfected with pRK5-GFP into HEK293 cells by Suprefact transfection regent. The protein expression was measured by immunofluorescence method and Western blot. The electrophysiological characteristics of transfected cells were determined by whole cell patch-clamp technique.

RESULTS

Direct sequence analyses revealed a C to T transition at position 1682. A561V mutation was correctly combined to eukaryotic expressive vector pcDNA3 and expressed in HEK293 cells. The protein expression of mutation and heterozygosis were located in cytoplasm and cellular membrane. 155 kDa and 135 kDa protein bands were detected in wild type HERG channel while only 135 kDa protein band was shown in heterozygous and mutational channels. Significant HERG tail-current was recorded in wild type HERG channel but not in mutation and heterozygosis channels.

CONCLUSION

This study evidenced a functional dominant-negative current suppression in HEK293 cells transfected with HERG mutation A561V.

[Construction of eukaryotic expression vector of congenital long QT syndrome related HERG gene A561V mutation and its expression in HEK293 cells]

OBJECTIVE

To investigate the protocol of the construction of HERG gene mutations, an A561V mutation which was detected in a Chinese congenital long QT syndrome (LQTS) family had been constructed and expressed in vitro.

METHODS

The A561V cloning vector PGEM-HERG-A561V was constructed by quick site-directed mutagenesis PCR. The A561V expressive vector pcDNA3-HERG-A561V was constructed by restriction enzymes. pRK5-GFP was cotransfected with pcDNA3-HERG-A561V or wild type pcDNA3-HERG into HEK293 cells by Superfect transfection reagent. The protein was measured by immunofluorescence.

RESULTS

Direct sequence analyses revealed a C to T transition at position 1682. The A561V mutation was correctly combined to eukaryotic expressive vector pcDNA3 and expressed in HEK293 cells. The protein of mutation was expressed in cytoplasm and cellular membrane while the wild type gene was expressed only on cellular membrane.

CONCLUSION

The protocol can be used successfully to construct and express HERG A561V mutation and it forms the basement of the further study on functions of mutation.

ST-segment elevation in the early repolarization syndrome, idiopathic ventricular fibrillation, and the Brugada syndrome: cellular and clinical linkage

ST-segment elevation in a structurally normal heart is associated with an electrocardiographic (ECG) J wave, which can be observed in the early repolarization syndrome (ERS), idiopathic ventricular fibrillation (VF), and the Brugada syndrome. Animal studies have demonstrated that the J wave is the consequence of a transmural voltage gradient resulting from an Ito-mediated action potential notch (spike and dome) in epicardium but not endocardium. Ito-mediated spike and dome morphology predisposes loss or depression of the dome in epicardium, leading to ST-segment elevation. Despite the fact that 3 clinical syndromes share many common ECG features, their clinical consequences are remarkably different. The ERS is a benign ECG finding characterized by a distinct J wave and ST segment in left precordial leads V4 through V6. In contrast, idiopathic VF and the Brugada syndrome, characterized by a J wave and ST-segment elevation in the inferior and right precordial leads, respectively, are the leading causes for sudden cardiac death in young Southeast Asian males. The underlying mechanism for such a difference in clinical consequences among these syndromes is due to a difference in Ito density and Ito-mediated epicardial spike and dome. When Ito is prominent, complete loss of the dome may occur due to either a decrease in inward currents or an increase in outward currents, leading to phase 2 reentry capable of initiating VF as in idiopathic VF and the Brugada syndrome. When Ito is relatively small as in the ERS, partial depression of the dome occurs without the development of phase 2 reentry.

Prevention of pericardial constriction by transcatheter intrapericardial fibrinolysis with urokinase

OBJECTIVE

To investigate whether intrapericardial urokinase irrigation along with pericardiocentesis could prevent pericardial constriction in patients with infectious exudative pericarditis.

METHODS

A total of 94 patients diagnosed as infectious exudative pericarditis (34 patients with purulent pericarditis and 60 with tuberculous pericarditis, the disease courses of all patients were less than 1 month), 44 males and 50 females, aged from 9 to 66 years (mean 45.4 +/- 14.7 years), were consecutively recruited from 1993 to 2002. All individuals were randomly given either intrapericardial urokinase along with conventional treatment in study group, or conventional treatment alone (including pericardiocentesis and drainage) in control group. The dosage of urokinase ranged from 200000 to 600000 U (mean 320000 +/- 70000 U). The immediate effects were detected by pericardiography with sterilized air and diatrizoate meglumine as contrast media. The long-term investigation depended on the telephonic survey and echocardiographic examination. The duration of following-up ranged from 8 to 120 months (mean 56.8 +/- 29.0 months).

RESULTS

Percutaneous intrapericardial urokinase irrigation promoted complete drainage of pericardial effusion, significantly reduced the thickness of pericardium (from 3.1 +/- 1.6 mm to 1.6 +/- 1.0 mm in study group, P < 0.001; from 3.4 +/- 1.6 mm to 3.2 +/- 1.8 mm in control group, P > 0.05, respectively), and alleviated the adhesion. Intrapericardial bleeding related to fibrinolysis was found in 6 of 47 patients with non-blood pericardial effusion and no systemic bleeding and severe puncture-related complication was observed. In follow-up, there was no cardiac death, and pericardial constriction events were observed in 9 (19.1%) of study group and 27 (57.4%) of control group. Cox analysis illustrated that urokinase could significantly reduce the occurrence of pericardial constriction (relative hazard coefficient = 0.185, P < 0.0001).

CONCLUSION

The early employment of intrapericardial fibrinolysis with urokinase and pericardiocentesis appears to be safe and effective in preventing the development of pericardial constriction in patients with infectious exudative pericarditis.

[Single nucleotide polymorphisms of genes associated with high density lipoprotein metabolism in Chinese population]

OBJECTIVE

To study the single nucleotide polymorphisms in genes associated with the high density lipoprotein (HDL) metabolism in Chinese population.

METHODS

Two hundred and nine normal Han ethnic subjects, aged 59+/-10 years, were recruited from 5 medical centers in western part of China. DNA was extracted by proteinase K digestion, phenol and chloroform extraction as well as isopropanol precipitation. The polymerase chain reaction (PCR)-restriction fragment length polymorphisms (RFLP) in conjunction with sequencing were employed to test the single nucleotide polymorphisms (SNPs) in ATP-binding cassette transporter (ABCA1), cholesteryl ester transfer protein (CETP) and lipoprotein lipase (LPL) genes.

RESULTS

The allelic frequencies of A and G of ABCA1 gene are 53.4% and 46.6%; of B2 and B1 allele of CETP, 41.0% and 59.0%; of HindIII (-) and (+) allele of LPL, 18.9% and 81.1%; and of PvuII(+) and (-) allele of LPL, 66.0% and 34.0%, respectively. All genotype frequencies fit well with the Hardy-Weinberg equilibrium; the significant linkage disequilibrium exists between LPL HindIII(+)and PvuII(+) polymorphisms. All of the RFLP in these genes result from the single nucleic substitution in fragment recognized by corresponding restriction enzymes.

CONCLUSION

The genetic polymorphisms of ABCA1, LPL-HindIII and LPL-PvuII in Chinese Han ethnic population are significantly different from Caucasians residing in USA or Europe.

Preclinical strategies to assess QT liability and torsadogenic potential of new drugs: The role of experimental models

The recognition of QT prolongation and torsade de pointes (TdP) in humans has resulted in the re-labeling of some drugs and the removal of others from the market in the past decade. Recent regulatory guidelines have recommended a battery of preclinical tests to assess a new drug for the QT liability in humans. The assessment includes the effect of a drug on: 1) the ionic current in stable cell lines expressing hERG channel; 2) action potential duration (APD) measured in isolated ventricular tissues; 3) the QTc interval and TdP in animals in vivo; and 4) APD, the QT interval, transmural dispersion of repolarization (TDR) and TdP potential in the isolated arterially-perfused ventricular wedge preparation. Because a noncardiac drug with an incidence of TdP even less than 0.1% can be potentially removed from the market, the experimental models used for preclinical testing have to be high sensitive and specific to the signals related to TdP. Among available experimental models, the rabbit left ventricle wedge preparation exhibits a high sensitivity and a high specificity in the identification of compounds positive and negative for QT prolongation and TdP. This is attributed to the fact that the preparation demonstrates strong signals related to QT prolongation in response to even a weaker QT prolonging agent. Signals specifically pertinent to the development of TdP, ie, early afterdepolarization (EAD) and an increase in TDR can be detected as well. The preclinical data obtained from the wedge preparation correlate well with clinical outcomes.

[Effects of Evan Blue on perfused dimension display and rabbit left ventricular action potential]

OBJECTIVE

Simultaneous recording of transmembrane action potential at endocardium, midcardium and epicardium and transmural ECG in arterially perfused left ventricular preparation is a new method for researching into the mechanism about ventricular arrhythmia, and in this connection, how to distinguish the perfused area plays a key role in keeping preparations under normal condition. This study is aimed to evaluate the effects of Evan Blue on the displaying of the perfused area and on the characters of transmembrane action potential of the arterially perfused left ventricular preparations.

METHODS

Rabbit left ventricular wedge preparations were perfused with Tyrode solution continuously via left circumflex, and the action potential of endocardium, midmyocardium, epicardium or transmural electrocardiogram were recorded simultaneously. The action poatential duration (APD), transmural dispersion of repolarization (TDR) or QT intervals were compared and the color variation of the preparations were studied before and 30 min after perfusion with Evan Blue.

RESULTS

Under the basic stimulatory cycle length of 1000, 2000, 4000 ms, there was no significant difference of APD in the same transmural layer or TDR before and after Evan Blue perfusion (P<0.01), but APD or TDR stimulated at basic cycle length of 1000-4000 ms were all higher than those recorded at 500 ms (P<0.01); APDs of endocardium were much longer than those of epicardium or midmyocardium (P<0.01); there was no significant difference in APD, TDR and QT intervals before and after Evan Blue perfusion (P>0.05). No premature ventricular contractions and ventricular tachycardia happened during the experiments.

CONCLUSION

Evan Blue can be used as a marker to identify the perfused area.

[Heterogeneity of Na+/Ca2+ exchanger current across the left ventricular wall of rabbit]

OBJECTIVE

To investigate the distribution characteristics of Na+/Ca2+ exchanger current (I(Na+/Ca2+)) across the left ventricular wall of rabbit and the relationship between I(Na+/Ca2+) and transmural depolarization heterogeneity.

METHODS

By using whole-cell patch clamp techniques, action potentials (AP), I(Na+/Ca2+), and both rapid and slow components of delayed rectifier potassium current (I(Kr) and I(Ka)) were recorded in subendocardial (Endo), midmyocardial (M), and subepicardial (Epi) cells of the left ventricular wall of rabbit.

RESULTS

AP duration in M cells was longer than that in Epi cells, P<0.01. At the test potential of +40 mV, outward I(Na+/Ca2+) in M cells was larger than that in Epi and Endo cells, P<0.01, P<0.05, respectively. At the test potential of -100 mV, inward I(Na+/Ca2+) in M cells was larger than that in Epi cells, P<0.05. At the test potential of +50 mV, the tail current density of I(Ka) in M cells was smaller than that in Epi cells, P<0.05, and there was no significant difference among the tail current densities of I(Kr) in Endo, M, and Epi cells.

CONCLUSION

The distribution of I(Na+/Ca2+) and I(Ka) across the left ventricular wall of rabbit is unequal, which contributes to the transmural depolarization heterogeneity.

[Long QT syndrome gene diagnosis by haplotype analysis]

OBJECTIVE

Three long QT syndrome(LQTS) pedigrees were brought together for genetic diagnosis by using short tandem repeat(STR) markers.

METHODS

Genomic DNA was extracted from blood samples. STR markers (D7S1824, D7S2439, D7S483, D3S1298, D3S1767, D3S3521) in or spanning the HERG and SCN5A gene were amplified; the haplotype analysis for LQTS was performed.

RESULTS

Clinical diagnosis showed that 15 are LQTS patients (3 died) and 11 are probable patients. Linkage analysis showed that LQTS patients are linked with the SCN5A gene in family 1, HERG is linked with the disease in family 2 and 3. Fourteen gene carriers were identified, 2 patients and 7 probable patients were excluded.

CONCLUSION

Linkage analysis using STR markers can serve as useful tool for presymptomatic diagnosis.

[Na+/Ca2+ exchanger current and K+ current remodeling in midmyocardial cells of hypertrophic left ventricle]

OBJECTIVE

To investigate the characteristics of Na+/Ca2+ exchanger current (INa+ /Ca2+) and K+ current remodeling in midmyocardial cells of hypertrophic left ventricle for understanding the ionic basis of arrhythmia of the hypertrophic heart.

METHODS

Twenty New Zealand rabbits were divided equally into normal control group and operation group, and in the latter, left ventricular hypertrophy was induced in the rabbits by partial ligation of the abdominal aorta. Action potentials, INa+/Ca2+, slowly activating delayed rectifier K+ current (IKs) and rapidly activating delayed rectifier K+ current (IKr) were recorded in the two groups by using whole-cell patch-clamp technique.

RESULTS

At the basic cycle length of 2 s, 90% action potential duration (APD90) in control and operation groups was 522.0+/-19.5 ms (n=6) and 664.7+/-32.7 ms (n=7) respectively; at the testing potential of +40 mV, outward INa+/Ca2+ density in the two groups was 0.94+/-0.11 pA/pF (n=9) and 1.30+/-0.11 pA/pF (n=8) respectively; the testing potential of -100 mV elicited inward INa+/Ca2+ density of 0.40+/-0.05 pA/pF (n=9) and 0.56+/-0.02 pA/pF (n=8) respectively. The testing potential of +50 mV induced IKs tail current density of 0.26+/-0.03 pA/pF (n=8) and 0.17+/-0.01 pA/pF (n=9), and IKr tail current density of 0.34+/-0.02 pA/pF (n=8) and 0.23+/-0.02 pA/pF (n=9) respectively. Statistically significant differences were identified between the control and operation groups in all the above indices measured.

CONCLUSION

The characteristics of electrical remodeling changes in midmyocardial cells of hypertrophic left ventricle, exhibited by prolonged action potential, up-regulated INa+/Ca2+ and down-regulated IKs and IKr.

In vivo distribution of c-myc antisense oligodeoxynucleotides local delivered by gelatin-coated platinum-iridium stents in rabbits and its effect on apoptosis

BACKGROUND

Post-stenting restenosis is a significant clinical problem, involving vascular smooth muscle cells (VSMCs) proliferation and apoptosis. It is reported that c-myc antisense oligodeoxynucleotides (ASODNs) local delivered by catheter can inhibit VSMCs proliferation. This study was designed to assess tissue distribution of c-myc ASODN local delivered using gelatin-coated platinum-iridium (Pt-Ir) stents, and its effect on apoptosis of VSMCs.

METHODS

Gelatin-coated Pt-Ir stents that had absorbed caroboxyfluorescein-5-succimidyl ester (FAM) labeled c-myc ASODNs (550 microg per stent) were implanted into the right carotid arteries of 6 rabbits. Tissue samples were obtained at 45 minutes, 2 hours, and 6 hours. Tissue distribution of c-myc ASODNs was assessed by fluorescence microscopy. In addition, 32 rabbits were randomly divided into two groups. Rabbits in the control group (n = 16) were implanted with gelatin-coated Pt-Ir stents, and those in the treatment group (n = 16) were implanted with gelatin-coated stents that had absorbed c-myc ASODNs. 7, 14, 30, or 90 days (n = 4, respectively, for each group) after the stenting procedure, the stented segments were harvested, and histopathological examinations were performed to calculate neointimal area and mean neointimal thickness. The expression of c-myc was assessed using in situ hybridization (ISH) and immunohistochemical methods. Apoptotic VSMCs were detected using terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) and transmission electron microscope (TEM).

RESULTS

According to fluorescence microscopic results, FAM-labeled c-myc ASODNs were concentrated in the target vessel media at the 45 minutes time point, and then dispersed to the adventitia. Morphometric analysis showed that neointimal area and mean neointimal thickness increased continuously up to 90 days after stent implantation, but that total neointimal area and mean neointimal thickness were less in the treatment group than in the control group at all time points (P < 0.0001). At day 7 and day 14 after stenting, there were no detectable apoptotic cells in either group. However, apoptotic cells were present in the neointima 30 and 90 days after stenting, and the number of apoptotic cells was less at 30 days than at 90 days. Meanwhile, c-myc ASODNs appeared to induce apoptosis in more cells in the treatment group than that in the control group. Typical apoptotic VSMCs were observable under TEM. The expression of c-myc was positive in the control group and negative or weakly positive in the c-myc ASODN treatment group, according to both ISH and immunohistochemical examination.

CONCLUSION

Gelatin-coated Pt-Ir stent mediated local delivery of c-myc ASODNs is feasible. The localization of c-myc ASODN is primarily in the target vessel walls. c-myc ASODNs can inhibit VSMCs proliferation and induce its apoptosis after local delivery in vivo.

Clinical characteristics of 5 Chinese LQTS families and phenotype-genotype correlation

In order to assess the clinical manifestations and electrocardiogram (ECG) characteristics of Chinese long QT syndrome (LQTS) patients and describe the phenotype-genotype correlation, the subjects from 5 congenital LQTS families underwent clinical detailed examination including resting body surface ECG. QT interval and transmural dispersion of repolarization (TDR) were manually measured. Five families were genotyped by linkage analysis (polymerase chain reacting-short tandem repeat, PCR-STR). The phenotype-genotype correlation was analyzed. Four families were LQT2, 1 family was LQT3. Twenty-eight gene carriers were (14 males and 14 females) identified from 5 families. The mean QTc and TDRc were 0.56 +/- 0.04 s (range 0.42 to 0.63) and 0.16 +/- 0.04 s (range 0.09 to 0.24) respectively. 35.7% (10/28) had normal to borderline QTc (< or = 0.460 s). There was significant difference in QTc and TDRc between the patients with symptomatic LQTS and those with asymptomatic LQTS, and there was significant difference in TDRc between the asymptomatic patients and normal people also. A history of cardiac events was present in 50% (14/28), including 9 with syncope, 2 with sudden death (SD) and occurred in the absence of beta-blocker. Three SDs occurred prior to the diagnosis of LQTS and had no ECG record. Two out of 5 SDs (40%) occurred as the first symptom. Typical LQT2 T wave pattern were found in 40% (6/15) of all affected members. The appearing-normal T wave was found in one LQT3 family. Low penetrance of QTc and symptoms resulted in diagnostic challenge. ECG patterns and repolarization parameters may be used to predict the genotype in most families. Genetic test is very important for identification of gene carriers.

[Effect of xuezhikang on blood lipids, serum oxidized low density lipoprotein, C-reactive protein and fibrinogen in patients with unstable angina pectoris]

OBJECTIVE

To study the lipid regulatory effect of Xuezhikang (XZK) and its effects on serum oxidized low density lipoprotein (OX-LDL), C-reactive protein (CRP) and fibrinogen (FIB) in patients with unstable angina pectoris (UAP).

METHODS

UAP patients with hyperlipidemia were treated with XZK 0.6 g, orally taken, twice a day for 2 successive months followed by half dosage for 2 months. To UAP patients with normal blood lipids, Vit E was given orally for 4 months. Levels of blood lipids, OX-LDL, CRP, FIB at the time of entry, 1st and 2nd month of the therapeutic course were observed and end-point events in the two groups was compared.

RESULTS

XZK can reduce the serum level of total cholesterol, low density lipoprotein after being administered for 1 month, and the effect further elevated after 2 months. Its effect in lowering triglycerides and increasing high density lipoprotein initiated after 2 months administration. Compared with effect of Vit E, XZK can significantly lower the serum OX-LDL, CRP and FIB after 2 months administration, and reduce the end-point events in 4 months.

CONCLUSION

XZK has good regulatory effect on blood lipids, it also can inhibit the development of inflammation in coronary plaque, therefore, is beneficial to the prognosis of UAP patients.