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Biomedical subjects

G Cui

Publications and source records attributed to G Cui.

31 records · Page 2Linked to original sources
PubMed1999

[Acute rupture of anterior cruciate ligament: diagnosis and treatment by early arthroscopy].

OBJECTIVE: To early diagnose and treat acute rupture of anterior cruciate ligament (ACL). METHODS: 23 patients with acute rupture of ACL were examined and treated by early arthroscopy. RESULTS: The preoperative diagnosis of ACL rupture was similar to that of in 18 patients. Three patients were confirmed by early arthroscopy and 2 patients were found to have ACL rupture, 16 patients were combined with meniscus injuries and 6 patients with cartilaginous injuries. Patholanatomical type of ACL were rupture of parenchymal part (21 patients) and avulsion rupture of attachment point (2 patients). In 6 patients ACL was reconstructed under arthroscope. CONCLUSIONS: Early arthroscopy in the treatment of acute ACL rupture has advantages of minor injury, correct diagnosis, visible location of injury or combined injury and timely treatment. Early arthroscopy for acute ACL rupture is an important measure for diagnosis, treatment, and stabilization of the knee joint.

Acute Disease↗
PubMed1998

Different Effects of Amiodarone and Quinidine on the Homogeneity of Myocardial Refractoriness in Patients With Intraventricular Conduction Delay.

BACKGROUND: Increases in QT and JT dispersion have been suggested as indicative of a proarrhythmic potential as a result of heterogeneity in myocardial refractoriness, the reduction of which by antiarrhythmic agents might be associated with a beneficial effect on the development of serious ventricular arrhythmias. METHODS: To test the hypothesis that amiodarone reduces the heter-ogeneity of ventricular refractoriness to a significantly greater extent than quinidine in patients with intraventricular conduction defects under treatment for ventricular arrhythmias, the corrected and uncorrected QT and JT intervals and dispersions from 12-lead surface electrocardiograms were determined in 120 patients with intraventricular conduction defects with cardiac arrhythmias before and during treatment with amiodarone (n = 60) and quinidine (n = 60). RESULTS: Amiodarone increased QT from 403 +/- 50 ms to 459 +/- 47 ms (P <.001), with a similar increase in the corrected QT interval (QTc) (P <.001). Amiodarone reduced QT dispersion by 40% (P <.001), whereas quinidine increased by 18% (P <.001). The net effects of both drugs were similar for OTc. Amiodarone, but not quinidine, reduced heart rate significantly; amiodarone had no effect on the QRS; but quinidine increased if (P <.001). Quinidine as well as amiodarone increased the JT and JTc intervals significantly, but the effect of quinidine was qualitatively less striking. Amiodarone decreased the JT dispersion by 33% (P <.001) and JTc dispersion by 37% (P <.001). On the other hand, quinidine increased the corresponding values for JT and JTc by 18% (P <.001) and 21% (P <.001), respectively. The overall data on QT and JT dispersion indicate an improvement in the homogeneity of myocardial refractoriness with amiodarone treatment and the converse with quinidine treatment; this observation is consistent with a lower proarrhythmic propensity and mortality with amiodarone than with quinidine. Quinidine increased the QRS interval more than amiodarone, and the data indicate that in patients with intraventricular conduction defects, the monitoring of the JT interval might more accurately reflect changes in myocardial repolarization. CONCLUSIONS: Amiodarone and quinidine both increased the corrected and uncorrected QT and JT intervals; amiodarone decreased and quinidine increased the dispersion of these intervals, and these results suggested an improvement in the homogeneity of myocardial refractoriness as a result of amiodarone treatment and the converse as a result of quinidine treatment. Quinidine increased the QTS interval more than amiodarone, and the data indicate that in patients with intraventricular conduction defects, the monitoring of the JT interval might more accurately reflect changes in myocardial repolarization.

Journal Article↗
PubMed1998

[An application of genetic algorithms to the analysis of EXAFS spectrum].

Extended X-ray absorption fine structure (EXAFS) has been extensively used in the structural study in recent years. But the current methods of analysis EXAFS spectrum is difficult and tedious,demanding either very similar standard samples or the initial parameters near the solution. In this paper, a new technique Genetic Algorithms (GAs), was applied to the analyzing of the EXAFS spectrum,and two spectra of CU samples were investigated by the method. It was found that reasonable results can be obtained by the method only with limiting the initial parameters to a broad range. Comparing the results with those obtained by EXCURVE88, the fitting is superior, and the parameters are reasonable. Therefore, it is proved that the GAs may be a high performance method for the analyzing of the EXAFS spectra.

Algorithms↗
PubMed1998

Electrophysiological effects of MS-551, a new class III agent: comparison with dl-sotalol in dogs.

MS-551 is a newly synthesized, nonspecific K+ channel blocker. To elucidate its electrophysiological and potential proarrhythmic effects relative to those of dl-sotalol in vivo, serial changes in ECGs, endocardial and epicardial monophasic action potential durations, and left and right ventricular pressures were measured simultaneously in pentobarbital-anesthetized open-chest dogs. Complete heart block was produced by the injection of 37% formaldehyde into the atrioventricular node. Intravenous administration of MS-551 produced prolongation of action potential duration at 90% repolarization time (APD90) immediately after the beginning of infusion and reached plateau at 10 min. MS-551 (1 mg/kg) caused 73 +/- 8% increase in APD90 and 28 +/- 5% increase in QTc at basic cycle length of 700 msec. The maximal prolongation of APD90 induced by 1 mg/kg MS-551 was 39% greater than that by the same dose of sotalol (P < .01). The dose-response curve of prolongation of ventricular effective refractory period produced by MS-551 was shifted significantly to the left compared with that induced by sotalol. The EC50 was 0.5 +/- 0.1 mg/kg and 1.2 +/- 0.2 mg/kg for MS-551 and sotalol, respectively (P < .05). When 0.5 mg/kg MS-551 doses were used, no ventricular arrhythmia was induced by stimulation at 200-msec basic cycle length. When 1.5 mg/kg sotalol was administered, 5 of 15 developed torsade de pointes, 2 of 15 developed ventricular fibrillation and 5 of 15 developed sustained ventricular tachycardia. The idioventricular rates and left ventricular pressures were reduced significantly by sotalol, not by MS-551. In conclusion, MS-551 is a potent class III antiarrhythmic agent that selectively prolongs repolarization in the ventricular myocardium and appears to be devoid of autonomic effects. Dose for dose, it is more potent in prolonging the APD90 and the right ventricular effective refractory period possibly with a lower tendency for the development of proarrhythmia in a canine heart-block model.

Action Potentials↗
PubMed1997

Study of simplified measures for malaria surveillance in the late consolidation phase in China.

This paper presents the results of a study on simplified surveillance methods conducted in 23 pilot counties in 11 provinces and municipalities in China where reside 15 million people and malaria control has been in the late consolidation phase. Two simplified surveillance Schemes (A and B) taking treatment of clinical cases as the main measure were implemented in 1992-1994. The rate of annual blood examination for case detection was 1.0% in pilot Scheme A, while in areas of scheme B it was 0.3%. The implementation of both Scheme A and Scheme B, simplified or without treatment of infection foci and management of mobile populations, acquired satisfactory effects against malaria. Consequently, malaria incidence was declining steadily, only a few indigenous and introduced cases were detected. The parasite rate in residents and the IFA positive rate in children were very low. The results of pilot studies and cost-effectiveness analysis indicated that Scheme B is effective, rational and economic, and can be implemented to replace the routine surveillance measures in areas where malaria has been at the late consolidation phase in China.

Adult↗
PubMed1997

[Long-term follow-up of 43 patients with Sjögren's syndrome].

OBJECTIVE: To study the long-term outcome in patients with Sjögren's syndrome (SS). METHODS: We retrospectively studied a cohort of 43 patients with SS; 31 patients with primary SS and 12 patients with secondary SS (6 patients with rheumatoid arthritis, 3 patients with mixed connective tissue disease, 2 patients with systemic lupus erythematosus and 1 patient with systemic sclerosis). Follow-up assessments were performed for 10-20 years following the initial diagnosis. RESULTS: During follow-up, 29 patients (67%) with SS developed new extraglandular manifestations including: a small amount of monoclonal gammopathy (10 patients), interstitial pulmonary disease (8 patients), malignancy (4 patients developed cancer, 1 patient developed malignant lymphoma), Raynaud's phenomenon (4 patient), peripheral neuropathy (3 patients), renal disease (2 patients), myopathy (2 patients) and others. Statistically significant differences in the salivary gland scintigraphy existed between the progressed group and the stable group at both the initial diagnosis and ten years later. Patients with anti-Ro (SS-A) antibody had a high incidence of salivary gland enlargement, hypocomplementemia, rheumatoid factor and anti-nuclear antibody. The focus scores of the labial salivary biopsy in anti-La (SS-B) antibody positive patients were significantly higher than in patients without this antibody. No statistically significant differences were noted in symptoms and signs between study entry and follow-up. CONCLUSIONS: Although sicca symptoms involving the eyes and the mouth did not progress in most of SS patients, 67.4% of SS patients developed new extraglandular manifestations during the 10-20 years follow-up period.

Adult↗
PubMed1996

Acute effects of thyroid hormone on inward rectifier potassium channel currents in guinea pig ventricular myocytes.

Thyroid hormones play an important role in cardiac electrophysiology. However, the regulation of cardiac ionic channels by thyroid hormones is still unclear. To evaluate the acute effect of 3,3',5-triiode-L-thyronine (T3) on inward rectifier potassium channel (IK1) action potentials, whole-cell IK1 currents and steady-state single IK1 currents were recorded in guinea pig ventricular myocytes. Acute exposure of cells to T3 resulted in shortening of the action potential durations. This effect was initiated at 5-15 min and reached a stable plateau at 25 min. The amplitude of steady-state whole-cell IK1 was significantly increased by T3 at 1 nM to 1 microM concentration rage and with ED50 12 nM/liter. T3 (1 microM) increased IK1 by 68 +/- 7% at -40 mV and 52 +/- 9% at -100 mV. Similar effects were observed with triiodothyroacetic acid, an analogue of T3 that does not stimulate DNA transcription. The single IK1 open probability (Po) was increased 7 +/- 1% by 1 nM T3 (n = 9, P < 0.05) and 42 +/- 6% by 1 microM T3 at -40 mV (n = 18, P < 0.0001). However, the channel unit amplitude, time constants of open and fast-closed time were not changed. T3 shortened interburst duration at each membrane potential but did not change the burst behavior. To elucidate detailed mechanism, we assumed a three-state model (C1 <==> C2 <==> O) and calculated each rate constant. T3 significantly increased the rate constant, k+1, for the transition from the C1 to the C2 state at RP -40 mV (2.84 +/- 0.56 to 7.28 +/- 1.23 sec-1, P < 0.01), RP -20 mV (3.63 +/- 0.95 to 10.17 +/- 2.60 sec-1, P < 0.05) and RP (6.73 +/- 1.20 to 21.94 +/- 4.49 sec-1, P < 0.01). However, the other rate constants were not affected. These results demonstrate that T3 enhances IK1 with the increment in Po, which mainly results from shortening of interburst duration without any changes in burst behavior. Hence, the shortening of interburst duration is due to acceleration of the transition from the C1 to the C2 state. The enhanced IK1 by T3 might be one of the causes for shortened action potential duration in hyperthyroidism.

Action Potentials↗
PubMed1994

Effects of amiodarone, sematilide, and sotalol on QT dispersion.

To study the effects of class III agents on QT/QTc dispersion in patients with heart disease and cardiac arrhythmias, QT dispersion and QRS and RR intervals were compared in patients before and after treatment with amiodarone (n = 26), sematilide (n = 26), and sotalol (n = 26). QT, QRS, and RR intervals, and QTc values were calculated for each complex, and their mean values were calculated for each lead. QT and QTc dispersions were defined as differences between the minimal and maximal QT or QTc values in each of the 12 leads studied. Amiodarone, sematilide, and sotalol all significantly prolonged the QT interval and the QTc value. Significant reductions in QT and QTc dispersions were only found in the amiodarone group (QT dispersions: 79 +/- 13 vs 49 +/- 14 ms; p < 0.001; QTc dispersions: 0.08 +/- 0.02 vs 0.05 +/- 0.01 s1/2; p < 0.001). The mean RR interval was significantly increased in patients after treatment with amiodarone (p < 0.001) and sotalol (p < 0.001), but not in patients receiving sematilide treatment (p > 0.2). The baseline QT and QTc dispersions were significantly greater in patients with than without myocardial infarction before treatment (p < 0.001). The mean baseline values for QT/QTc dispersions were not significantly different among all 3 groups. However, only amiodarone significantly reduced the QT dispersion (from 76 +/- 10 to 46 +/- 11 ms; p < 0.001) and QTc dispersion (from 0.09 +/- 0.02 to 0.05 +/- 0.01 s1/2; p < 0.001) in patients with myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Persistence and extinction of a population in a polluted environment.

Models of the persistence and extinction of a population or community in a polluted environment have been investigated in several papers. But all of those papers have a basic assumption that the capacity of the environment is so large that the change of toxicants in the environment that comes from uptake and egestion by the organisms can be neglected. This assumption is not made in this article. Some sufficient conditions on persistence or extinction of a population have been obtained, and the threshold between the two has also been obtained for most situations.

Environmental Pollution↗