Biomedical subjects

P Liu

Publications and source records attributed to P Liu.

At least 109 records · Page 6Linked to original sources

PubMed2000

Late arrhythmia in adults with the mustard procedure for transposition of great arteries: a surrogate marker for right ventricular dysfunction?

OBJECTIVE: To examine the relation between ventricular dysfunction and late clinical arrhythmia in adults who underwent the Mustard procedure for transposition of the great arteries. DESIGN: Observational study based on periodic outpatient assessment of biventricular function. SETTING: Tertiary referral centre. INTERVENTIONS: Analysis of data from 12 lead ECGs, echocardiography, exercise radionuclide ventriculography, and magnetic resonance imaging. MAIN OUTCOME MEASURES: Clinical outcome and late onset clinical arrhythmia during follow up. ECG and ventricular function indices obtained before arrhythmia onset were used for analysis. RESULTS: 51 patients (mean (SD) age 25.7 (5.0) years) fulfilled entry criteria at a mean of 23.4 (4.0) years after the Mustard procedure. Late arrhythmia occurred in 11 (22%): sustained atrial flutter/fibrillation in 10, ventricular tachycardia in one. Compared with patients who remained arrhythmia free, patients with arrhythmia had longer QRS (129 (26) v 112 (16) ms, p = 0.01), greater QT dispersion (107 (28) v 51 (24) ms, p < 0.001), and increased ratio of right to left ventricular end diastolic diameter (2.4 (0.9) v 1.7 (0.7), p = 0.02), but no difference in wall thickness. Systemic ejection fraction was also reduced in the arrhythmia subgroup (at rest: 34.1 (13)% v 47 (16)%, p = 0.04; during exercise: 37.8 (12)% v 52 (17)%, p = 0.03). QRS duration correlated with right ventricular end diastolic diameter (r = 0.59, p < 0.001), suggesting a possible mechano-electric relation after the Mustard procedure. QT dispersion was the only predictor of clinical arrhythmia in multivariate analysis. CONCLUSIONS: Impaired ventricular function in adults with the Mustard procedure for transposition of the great arteries relates to clinical arrhythmia. Late atrial flutter/fibrillation may be a surrogate marker for ventricular dysfunction, and these patients may also be at risk of ventricular tachycardia.

Adult↗

PubMed2000

Peroxynitrite attenuates hepatic ischemia-reperfusion injury.

In the present study, we examined the effects of peroxynitrite on reperfusion injury using a rat model of hepatic ischemia-reperfusion (HI/R). The left and median lobes of the liver were subjected to 30 min of ischemia, followed by 4 h of reperfusion. Groups A and B rats were sham-operated controls that received vehicle or peroxynitrite; groups C and D rats were subjected to HI/R and received peroxynitrite or vehicle, respectively. A dose of 2 micromol/kg body wt of peroxynitrite, diluted in saline (pH 9.0, 4 degrees C), was administered as a bolus through a portal vein catheter at 0, 60, and 120 min after reperfusion. Results showed that superoxide generation in the ischemic lobes of the liver and plasma alanine aminotransferase (ALT) activity of group C were decreased by 43% and 45%, respectively, compared with group D. Leukocyte accumulations in the ischemic lobes of liver and circulating leukocytes were decreased by 40% and 27%, respectively, in group C vs. D. The ratios of mRNA of P-selectin and intercellular adhesion molecule-1 (ICAM-1) to glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA extracted from the ischemic lobes of the liver of group C were decreased compared with group D. There were no differences between the groups A and B in terms of plasma ALT activity, circulating leukocytes, superoxide generation, and leukocyte infiltration in the ischemic lobes of the liver. Moreover, hemodynamic parameters (i.e., mean arterial blood pressure, cardiac index, stroke index, and systemic vascular resistance) were not significantly different among groups B, C, and D. These results suggest that administration of peroxynitrite via the portal vein only has a local effect. Exogenous peroxynitrite at physiological concentrations attenuates leukocyte-endothelial interaction and reduces leukocyte infiltration. The mechanism of the reduction of leukocyte infiltration into ischemic lobes of the liver appears because of decreased expression of mRNA of P-selectin and ICAM-1. The net effect of administration of peroxynitrite may be to reduce adhesion molecule-mediated, leukocyte-dependent reperfusion injury.

Alanine Transaminase↗

PubMed2000

Clinical application of neuroendoscopic techniques.

We treated 126 patients with different neurosurgical diseases by performing endoscopic neurosurgery, endoscopy-controlled microneurosurgery and endoscopy-assisted microneurosurgery. The indications were intracranial cysts in 51 patients, brain cysticercosis in 10 patients, hydrocephalus in 31 patients, and epidermoid cysts in 34 patients. The follow-up period ranged from 6 to 24 months (mean follow-up duration 9 months). After operation, 115 of 126 patients had improvement in their initial symptoms, 7 had no change and 4 developed complications, including subarachnoid hemorrhage (SAH), intraventricular hemorrhage, and transient cardiopulmonary dysfunction. It is concluded that (1) neuroendoscopic techniques show a distinct value in the treatment of deep-seated, intracranial diseases, or ventricle and cistern lesions; (2) neuroendoscopic techniques play an important role in microneurosurgery and consequently improve surgical quality; (3) the benefits of neuroendoscopic techniques include less surgical manipulation and trauma, milder postoperative reaction, decreased expenses and shortened hospitalizations.

Adolescent↗

PubMed2000

A role for hyaluronan in macrophage accumulation and collagen deposition after bleomycin-induced lung injury.

Elevated concentrations of hyaluronan (HA) are associated with the accumulation of macrophages in the lung after injury. We have investigated the role of HA in the inflammatory and fibrotic responses to lung injury using the intratracheal instillation of bleomycin in rats as a model. After bleomycin-induced lung injury, both HA content in bronchoalveolar lavage (BAL) and staining for HA in macrophages accumulating in injured areas of the lung were maximal at 4 d. Increased HA in BAL correlated with increased locomotion of isolated alveolar macrophages. HA-binding peptide was able to specifically block macrophage motility in vitro. Importantly, systemic administration of HA-binding peptide to rats before injury not only decreased alveolar macrophage motility and accumulation in the lung, but also reduced lung collagen alpha (I) messenger RNA and hydroxyproline contents. We propose a model in which HA plays a critical role in the inflammatory response and fibrotic consequences of acute lung injury.

Amino Acid Sequence↗

PubMed2000

A SXRF method for determining the relative concentration of trace elements in plasma protein affected by cisplatin.

This article presents an analytical method for the determination of the relative concentrations of trace elements in plasma protein by gel chromatography combined with SXRF (synchrotron radiation X-ray fluorescence). The fraction of plasma protein of male Kunming mice (body weight 24.2 +/- 0.3 g), treated with a cisplatin i.p. injection at a dose of 10 mg/kg, was obtained by the separation of a Sephadex G-50 column (buffered with ammonium acetate, pH 5.7). The SXRF experiments were performed at the Beijing Electron Positron Collider synchrotron radiation facility. The elements (Pt, S, Ca, Fe, Ni, Cu, Zn, Se, Br, and Sr) in the fraction of the plasma proteins (>22 kDa) were assayed using highly sensitive SXRF. The relative concentrations of elements were calculated by a normalization of Compton scattering intensity around 22 keV, after the normalization for the collection time of the X-ray spectrum and the counting of the ion chamber, and subtracting the contribution of the polycarbonate film for the supporting sample. The determination could prove that the element Pt in plasma was bound with macromolecular protein. Cu and S were present in the fraction of the protein in mice treated with cisplatin increase, and their ratios of treated/control were 1.66 +/- 0.06 and 1.78 +/- 0.33, respectively; Zn decreased to a ratio of 0.78 +/- 0.09. Our results are in agreement with others that cisplatin exposure leads to a marked loss of kidney copper and a moderate rise in kidney zinc. However, this article primarily describes one of the analytical methods used; it does not emphasize the results of the effect of cisplatin on trace elements in plasma protein.

Animals↗

PubMed2000

Transforming growth factor-beta and response to anticancer therapies in human liver and gastric tumors in vitro and in vivo.

Liver cancer and gastric cancer are the most common solid tumors worldwide. Transforming growth factor-beta (TGF-beta) production and lack of response to TGF-beta growth inhibitory effects have been associated with tumor progression and therapeutic resistance. HepG2, Hep3B, and SK-HEP-1 human liver cancer lines produce 3, 5.7, and 2.5 ng TGF-beta1; 1.4, 2, and 4 ng TGF-beta2 and 0.15, 0.2 and 0.22 ng TGF-beta3 per 107 cells (24 h). Expression of the TGF-beta type I receptor is 20x, 1x, and 0.6x the level in mink lung MvLu1 cells in the HepG2, Hep3B, and SK-HEP-1 cells, respectively. HepG2 and Hep3B cells do not express the TGF-beta type II receptor while SK-HEP-1 cells express 7x the level found in mink lung MvLu1 cells. Hs 746T, KATO III, RF-1, and RF-48 human gastric cancer cell lines produce 12. 5, 0.35, 0.4, and 0.4 ng TGF-beta1; 2.6, 0.95, 0.5, and 0.52 ng TGF-beta2 and 0.42, 0.17, 0.12, and 0.14 ng TGF-beta3 per 107 cells (24 h). Expression of TGF-beta type I receptor is 0.7x, 0.7x, 0.8x, 0.6x the level in mink lung MvLu1 cells in the Hs 746T, KATO III, RF-1 and RF-48 cells, respectively. KATO III cells are lacking in the TGF-beta type II receptor while Hs 746T, RF-1 and RF-48 cells express 10x, 0.8x, and 1x the levels in mink lung MvLu1 cells. The IC50 for TGF-beta1 is >>10 ng/ml in all of these lines except RF-48 where TGF-beta1 is mitogenic. The response of the cell lines to radiation, doxorubicin, mitomycin C, cisplatin, 5-fluorouracil, methotrexate, and gemcitabine showed that SK-HEP-1 was the most drug resistant liver cancer cell line and KATO III was the most drug resistant gastric cancer cell line. Overall, there was no correlation between TGF-beta secretion in cell culture and sensitivity of the cells to anticancer agents. Increased TGF-beta1 levels were detectable in the plasma of nude mice bearing Hep3B and Hs 746T xenografts. Those tumors which secreted greater amounts of TGF-beta were more therapeutically resistant in vivo.

Activin Receptors, Type I↗

PubMed2000

[Expression of CPP32, Fas and Fas ligand and the relationship between their expression and viral antigens in chronic hepatitis].

OBJECTIVE: To study the significance of Fas-Fas ligand (FasL)-CPP32 mediated hepatocytic apoptosis and the relationship between their expression and hepatitis C virus (HCV) antigens in pathogenesis of chronic hepatitis C (CHC). METHODS: The expression of Fas and FasL proteins and CPP32 protease and their mRNAs was detected by immunohistochemistry and in situ hybridization respectively. Meanwhile, HCV core protein and nonstructural protein NS(3) and NS(5) were examined on the sequential liver tissue sections from 65 cases of patients with CHC and 5 cases of normal subjects. The positive staining was quantified by image analysis. RESULTS: In CHC liver tissues, CPP32 protease, Fas and their mRNAs were mainly expressed in the hepatocytes, especially in the HCV core protein-positive hepatocytes and their surroundings, but FasL protein and its mRNA were expressed dominantly in the infiltrating mononuclear cells in the portal area and hepatic sinusoid. According to the increase of histological activity index (HAI) in the CHC liver tissues, the expression of the three proteins (protease) and their mRNAs were upregrulated obviously. CONCLUSION: The results suggest i) that Fas-FasL-CPP32 system is associated with HAI of CHC, ii) that HCV core antigen may affect the expression of CPP32 and Fas hepatocytes apoptosis.

Caspase 3↗

PubMed2000

Effects of carbon tetrachloride-injured hepatocytes on hepatic stellate cell activation and salvianolic acid A preventive action in vitro.

OBJECTIVE: To investigate the effects of carbon tetrachloride (CCl(4))-injured hepatocyte on hepatic stellate cell (HSC) activation, the relation between lipid peroxidation and liver fibrosis, and the action mechanisms of salvianolic acid A (SA-A), one of water soluble components extracted from radix salvia miltiorrhizae, against HSC activation and liver fibrosis. METHODS: The hepatocytes were isolated from the normal rats, incubated with SA-A at different concentrations, respectively, and vitamin E severed as control. At the same time the cells were fumigated with CCl(4) for 24h, and ALT activities in the medium were measured. After the cell medium was changed and cultured for another 24h, the medium was collected as "hepatocyte conditioned medium" (HCM) and measured for malondiadehyde (MDA) content. Then HCM was incubated with primary cultured HSC for 48h, and HSC proliferation, type I collagen gene expression and protein production were observed. RESULTS: ALT activity and MDA content in the hepatocyte medium were increased remarkably after the cell was injured. HCM could obviously promote HSC proliferation, type I collagen mRNA expression and protein production. SA-A could markedly inhibit ALT activity and MDA content in hepatocytes, and decreased collagen gene expression and protein production. CONCLUSION: The secretion from the peroxidative injured hepatocyte could stimulate HSC activation, SA-A could decrease activation by alleviation of hepatocyte peroxidation.

Alanine Transaminase↗

PubMed2000

[Chromosome localization of the dentinogenesis imperfecta type II locus].

OBJECTIVE: To scrutinize the linkage between dentinogenesis imperfecta type II and chromosome 4q21 in a Tianjin-Tanggu family. METHODS: Blood samples were collected from 13 members of the family. DNA was analyzed with 4 short tandem repeat polymorphisms markers UGATA62A11, DSP(P), SPP1 and D4S1563 Y using fluorescence-based PCR. The linkage between four markers on chromosome 4q21 and dentinogenesis imperfecta type II was tested by Lod score analysis. RESULTS: GATA62A11 and DSP(P) suggested linkage and yielded a Lod score of 1.63 at theta =0, and 1.68 at theta =0 by means of the MLINK software, respectively. Genotype and haplotype were acquired. CONCLUSION: The disease gene of the dentinogenesis imperfecta type II family is located on chromosome 4q. The result will be helpful for the further identification of the dentinogenesis imperfecta type II gene.

Chromosome Mapping↗

PubMed2000

Clinical classification of chronic prostatitis: a preliminary investigation.

AIM: To propose a practical clinical classification for the chronic prostatitis (CP). METHODS: The clinical features and the findings in the expressed prostatic secretion (EPS) in 804 cases of CP patients were retrospectively analyzed. RESULTS: Four types of CP were identified based on the clinical manifestations and the amounts of white blood cells (WBC) and lecithin in EPS. They were the latent type (85 cases; 10.6%), the common type (423 cases; 52.6%), the persisting type (104 cases; 12.9%), and the active type (192 cases, 23.9%). The therapeutic efficacy for these 4 subtypes were 40.4%, 76.8%, 30.8% and 37%, respectively; a statistical difference was noticed between the common type and the persisting type (P < 0.01). CONCLUSION: The method of classification proposed by the authors may help clinicians in the diagnosis and predicting the prognosis of CP.

Adult↗

PubMed2000

Effects of salvianolic acid-A on rat hepatic stellate cell proliferation and collagen production in culture.

AIM: To investigate the effects of salvionolic acid-A (SA-A), one of main effective components of Salvia miltiorrhiza for its antifibrotic action, on the cell proliferation and collagen production in cultured hepatic stellate cells (HSC). METHODS: HSC were isolated through in situ perfusion of liver with pronase E and collagenase, and gradient centrifugation with Nycodenz. The cultured HSC were incubated with SA-A 0.1-100 mumol/L for 24 h. MTT spectrometric assay and intercellular incorporation of methyl-[3H]thymidine ([3H]TdR) was used to assess the cell proliferation. The amount of collagen was semi-quantified by ponceau staining and image analysis, the amount of type I collagen secretion was measured with ELISA and normalized by the total protein of cell layer. The total RNA was prepared from the control cells and the drug treated cells respectively, and the expression of pro-collagen alpha 2 (I) mRNA was semi-quantitatively analyzed with RT-PCR. RESULTS: SA-A 100 mumol/L showed a little cytotoxity, SA-A 0.1-10 mumol/L did not influence cell morphology, and SA-A 1-100 mumol/L decreased the cell proliferation significantly in a concentration-dependent manner (P < 0.05). SA-A 1, 10, 100 mumol/L decreased the cell collagen deposition by 78.6%, 71.8%, and 61.3% of the control respectively (P < 0.05), and decreased type I collagen secretion to 53.1%, 52.6%, and 49.5% (P < 0.01 or P < 0.05). Both SA-A 1 and 10 mumol/L downregulated procollagen alpha 2 (I) mRNA expression remarkably (P < 0.05). CONCLUSION: SA-A inhibited HSC proliferation and collagen expression. The inhibitory effect on HSC activation is the main mechanism of SA-A action against liver fibrosis.

Animals↗

PubMed2000

[Field epidemiological and experimental study on relationship between genetic factor and nonresponse or hyporesponse to hepatitis B vaccine].

OBJECTIVE: To evaluate the role of genetic factor in the development of nonresponder or hyporesponder to hepatitis B vaccine in Chinese people from field epidemiology and experimental study. METHODS: Six hundred and thirty-four susceptible healthy students were vaccinated with three doses of plasma-derived hepatitis B vaccine. Twenty-nine non- or hypo-responders (subjects) and 30 hyperresponders (controls) as well as their 80 and 79 first degree relatives were determined and recruited in the study. The first degree relatives of subjects and controls were then immunized with hepatitis B vaccine and followed up. On the basis of the above results, alleles of HLA-A, B, C, DR and DQ locus were further detected in the two groups. RESULTS: The non- and hypo-response rate in immunized students was 4.6% (29/634). After administered with hepatitis B vaccine, the first degree relatives of the subjects displayed a 17.9% frequency of nonresponsiveness, higher than in the controls. The phenotype frequency of HLA-DR7 and B54 was 52.2% and 21.7% in subjects, 9.1% and 0.0% higher than in controls, respectively. The extended haplotype B54-DR7 was more frequent in the former (17.0%) than in the latter (0.0%) (P < 0.01). CONCLUSION: These results demonstrated that the genetic factor was likely associated with the non- and hypo-response to hepatitis B vaccine in Chinese people.

Adolescent↗

PubMed2000

[Clinical study on shenmai injection in promoting postoperative recovery in patients of breast cancer].

OBJECTIVE: To investigate the effect of Shenmai injection in promoting postoperative recovery of patients with breast cancer. METHODS: Eighty postoperative patients of breast cancer were selected and divided into two groups, the treated group (40 cases) was given intravenous Shenmai injection for 7 days and compared with the control group (40 cases) in wound healing time, postoperative drainage volume, complication and blood picture, and the NK cell, T-lymphocyte subsets (CD3, CD4, CD8), were compared before and after treatment. RESULTS: The wound healing time and postoperational complication in the treated group were less than those in the control group significantly. There was no difference between the two groups in WBC and platelet count, but the recovery of hemoglobin in the treated group was quicker than that in the control group significantly (P < 0.05), as comparing with the control group, the NK cell, CD4, CD4/CD8 ratio in the treated group were elevated faster than those in the control group significantly (P < 0.05). CONCLUSION: Shenmai injection was beneficial to the recovery of postoperative patients of breast cancer, to reducing the occurrence of complication and was favorable to conduct postoperative chemotherapy smoothly.

Adult↗

PubMed2000

[Cervical spine operation using coralline hydroxyapatite].

OBJECTIVE: To study the result of using coralline hydroxyapatite (CHA) in cervical anterior fusion and posterior laminoplasty operation. METHODS: 45 patients of cervical operation using CHA were followed up. Of these patients, 27 received anterior fusion and titanium plate fixation (34 levels fused). 18 with spinal stenosis at least at 3 levels, (posterior spinal process-splitting laminoplasty) had 79 split spinal processes fused by CHA. The average follow-up time was 25.9 months. RESULTS: The union rate of CHA was 85.3% in average by anterior approach. The height and angle of the fused level and the anterior salient were well maintained. The JOA score improvement rate was 58.7%. The CHA grafts were kept well between the split spinous processes with a union rate of 70.9%. After operation, the spinal cord moved dorsally, and the flat rate was improved from 0.19 to 0.41. No apparent posterior salient occurred. The JOA score improvement rate was 51%. CONCLUSION: The effect of CHA in cervical antero posterior operation is similar to that of autograft bone, and it is unnecessary to resect a piece of bone from a health region of the body.

Adult↗

PubMed2000

[Application of extracardiac conduit total cavopulmonary anastomosis].

OBJECTIVE: To evaluate the value of application of extracardiac conduit total cavopulmonary anastomosis (TCPA) in complex heart disease. METHODS: From June 1998 to August 1999, 10 patients with functional univentricular complex congenital heart diseases received TCPA. Eight patients were male and 2 female with a mean age of (9.0 +/- 5.6) years (from 2.5 to 21 years) and a mean weight of (25 +/- 14) kg (from 11 to 45 kg). Associated heart anomalies were TGA, PS or ASD. All surgical procedures were performed under general anesthesia and hypothermia. RESULTS: No operative and postoperative deaths and all patients were followed up for 6 - 18 months. All patients were clinically asymptomatic. There was no increase of systemic venous pressure. EKG revealed no arrhythmias. The cardiac function was in NYHA class I-II. CONCLUSIONS: Extracardiac conduit TCPA is a simple procedure and it is superior to others.

Adolescent↗

PubMed2000

[Inhibition of monocytes adhesion to the intima of arterial wall by local expression of antisense monocyte chemotactic protein-1].

OBJECTIVE: To study the mechanism of monocyte recruitment in atherogenesis and to clarify the effect of monocyte chemotactic protein-1 (MCP-1) in this process. METHODS: Femoral arteries isolated from the rabbits which had been fed with a high cholesterol diet and locally perfused with MM-LDL within the artery beforehand, were used as the models. Antisense MCP-1cDNA was transferred into the arterial wall by injecting recombinant LNCX-anti-MCP-1/liposomal complex in the femoral sheath and the periarterial tissue. RESULTS: Expression of antisense MCP-1 mediated by recombinant LNCX plasmid/lipsomal complex gene transfer enabled to inhibit MCP-1 gene expression and adhesion of monocyte to the intima. CONCLUSION: MCP-1 plays an important role on the recruitment of monocytes in the arterial wall, which provides a potential clue in developing a gene therapy project for the prevention and treatment of atherogenesis.

Animals↗

PubMed2000

[Seven years' summary report on the treatment of acute promyelocytic leukemia with arsenic trioxide--an analysis of 242 cases].

OBJECTIVE: To observe the effectiveness of arsenic trioxide (As(2)O(3)) in the treatment of acute promyelocytic leukemia (APL). METHODS: Data of clinical observation, seven year follow-up survey were analysed with American SAS system software, concentration of arsenic in cerebrospinal fluid (CSF) was determined by atomic absorbing spectrum. RESULTS: The complete remission (CR) and effectiveness rates were 87.9% and 94.4% for the previously untreated group; 60.0% and 65.0% for the relapsed in As(2)O(3) maintenance treatment group; 69.5% and 84.8% for the relapsed in other than As(2)O(3) maintenance treatment group; and 48.7% and 94.1% for the refractory group, respectively. In the previously untreated group, the relapse rate at 3 years after CR was 26.7%. The probability of survival in 136 follow-up survey patients was 92.0% and 76.7% at 5 years and 7 years, respectively. There were mild side effects. Central nervous system leukemia (CNSL) occurred in 138 out of 412 cases in 6 years, including some refractory leukemia, extramedullary residual leukemia and extramedullary relapse. Prophylactic intrathecal injection could reduce the incidence rate of CNSL. Determination of arsenic concentration indicated that it was difficult for arsenic to penetrate the blood-brain barrier. CONCLUSION: The CR rate and long-term survival are high and the relapse rate is low in APL patients treated with As(2)O(3). There is no cross-resistance between ATRA and As(2)O(3) and other chemotherapeutic agents. As(2)O(3)-resistance occurs scarcely. It can also be used in maintenance treatment.

Adolescent↗

PubMed2000

A comparison of calcitonin gene-related peptide effects on coronary flow and cardiac conduction system in the guinea pig.

The purpose of this study was to examine the effects of calcitonin gene-related peptide (CGRP) on coronary flow and various parts of cardiac conduction system (CCS) in the isolated guinea pig heart by recording the cardiac electrogram and His bundle activity simultaneously. The coronary flow (CF) was measured and the right atrium was paced at incremental frequencies periodically. Perfusing heart with CGRP at the concentrations of 3 30 nmol/L increased CF strikingly and dose-dependently. CGRP (30 nmol/L) caused a moderate and significant increase in the spontaneous heart rate, but failed to influence the atrioventricular nodal and His bundle-Purkinje fiber conduction time and the longest atrial pacing cycle length inducing 3 2 Wenckebach and 2 1 AV nodal conduction. The results indicate that CGRP in the guinea pig heart might act mainly on coronary vessels and then the sinus node, but did not affect the conductivity and refractoriness of the AV conduction system.

Animals↗