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Biomedical subjects

R L Sun

Publications and source records attributed to R L Sun.

At least 19 recordsLinked to original sources
PubMed2002

Medical prevention of space motion sickness--animal model of therapeutic effect of a new medicine on motion sickness.

Space motion sickness (MS) is one of the most important problems in the field of space medicine. In order to prevent space MS, a new medicine, PMPA, has been prepared by means of synthesizing in our laboratory. The purposes of this study were to set up animal models of PMPA against MS, and to observe its effects on anti-MS, and to prove its function of antagonism to choline. Eight cats, forty rabbits and two hundred and ten rats were selected as animal subjects. The parallel swing stimulus, a method causing the reversal syndromes and tests of anti-choline function were used in our experiments. The results are as follows: (1) The score of MS symptoms in cats with PMPA or scopolamine (SCOP) is significantly lower than that in cats with placebo (p<0.01), while the incidences of efficiency and prevention of PMPA (87.5%, 75%) are higher than those of SCOP (75.0%, 50%) in cats. (2) PMPA of 1.6 mg/kg or 0.8 mg/kg could antagonize the reversal syndromes and repress reversal rotation significantly in rabbits like SCOP in comparison with placebo (p<0.01). (3) PMPA could inhibit tremor evoked by oxotremorine or by nicotine-procaine in rats like SCOP, and play an important role in the antagonism to central M-choline and N-choline receptors. The animal experiments demonstrate that PMPA is an effective medicine against MS with antagonism function to choline.

Acceleration↗
PubMed2000

Benchmarking the clinical orthodontic evidence on Medline.

The purpose of this study was to identify and quantify the availability of orthodontic literature for evidence-based clinical decision-making (ie, sound clinical studies of etiology, diagnosis, treatment, or prognosis meeting basic methodologic criteria for direct clinical use). This is a first step toward developing online decision analysis systems. A search strategy based on Medical Subject Headings (MeSH) for orthodontics was developed to examine MEDLINE using the Ovid Web Gateway search engine. Sensitive and specific methodologic search filters were then employed to identify the 4 categories of information. The results were then subdivided by year to identify trends and sorted to identify source of publications. In the period 1990 to 1998, the MEDLINE searches identified 6938 English-language articles about orthodontics. The mean number of articles (+/-SD) per year ranged from 42+/-25 for specific searches to 314+/-214 for sensitive searches. The number of articles identified by the specific or sensitive searches increased 14% to 21% annually. When subdivided by clinical category, the mean numbers of articles per year for specific and sensitive searches were respectively: etiology 19+/-15 and 91+/-37, diagnosis 11+/-5 and 80+/-35, therapy 3+/-1 and 50+/-23, and prognosis 10+/-7 and 93+/-33. Five dental journals accounted for nearly half of these publications. These results provide several key findings: (1) there is a substantial literature of clinically relevant information in orthodontics upon which to base clinical decisions; (2) the information appears to be balanced between etiology, diagnosis, treatment, and prognosis; (3) approximately 45% of the articles reside in 5 journals, whereas the remainder reside in approximately 66 other journals, making it difficult to stay current; (4) the number of articles is increasing significantly each year; (5) to stay current, one would need to read between 1 and 6 articles per week, 52 weeks per year; (6) these trends suggest the need for computer-based clinical knowledge systems; and (7) the methods used here can be immediately employed to identify the best and most current clinical orthodontic evidence.

Analysis of Variance↗
PubMed1999

An analysis of 412 cases of hepatocellular carcinoma at a Western center.

OBJECTIVE: Using a large single-institution experience at a Western referral center, the authors examine partial hepatectomy as treatment of hepatocellular carcinoma and relate treatment outcomes to clinical parameters, including the etiology of underlying cirrhosis. METHODS: Four hundred and twelve patients seen between December 1991 and January 1998 were identified in a prospective database. Data about the surgical procedure, perioperative complications, and long-term outcome were examined. RESULTS: One hundred twenty-six patients did not have underlying cirrhosis. Of the 286 patients with cirrhosis, 119 were the result of hepatitis B, 39 hepatitis C, 36 both B and C, 43 ethanol abuse, and the remainder other causes. Two hundred forty-three patients underwent surgical exploration, and 154 patients underwent hepatic resection. Seven (4.5%) died from the surgery. One hundred forty-three patients were treated by ablative methods. Patients with cirrhosis had smaller tumors but nevertheless had a lower resectability rate. Neither the presence of cirrhosis nor the etiology of the cirrhosis altered the perioperative morbidity or mortality rate. The greatest determinant of long-term outcome was resectability. The size of the lesion, an alpha-fetoprotein level >2000 ng/ml, and vascular invasion were also determinants of poor outcome. The presence of cirrhosis was a detrimental factor when analysis was stratified for size of tumor. The cause of cirrhosis did not influence the long-term outcome. The 5-year survival rate was 57% for patients with resected lesions <5 cm and 32% for patients with tumors >10 cm. CONCLUSION: Partial hepatectomy is safe, effective, and potentially curative therapy for hepatocellular carcinoma. The presence of cirrhosis did not affect the surgical mortality rate but did affect the long-term survival rate. The cause of cirrhosis did not influence outcome. As treatment for small hepatocellular carcinomas, partial hepatectomy produces results similar to those of transplantation. For patients with large tumors who are poor candidates for transplantation, resection results in long-term survival in one third of patients.

Carcinoma, Hepatocellular↗
PubMed1999

Clinical score for predicting recurrence after hepatic resection for metastatic colorectal cancer: analysis of 1001 consecutive cases.

OBJECTIVE: There is a need for clearly defined and widely applicable clinical criteria for the selection of patients who may benefit from hepatic resection for metastatic colorectal cancer. Such criteria would also be useful for stratification of patients in clinical trials for this disease. METHODS: Clinical, pathologic, and outcome data for 1001 consecutive patients undergoing liver resection for metastatic colorectal cancer between July 1985 and October 1998 were examined. These resections included 237 trisegmentectomies, 394 lobectomies, and 370 resections encompassing less than a lobe. The surgical mortality rate was 2.8%. RESULTS: The 5-year survival rate was 37%, and the 10-year survival rate was 22%. Seven factors were found to be significant and independent predictors of poor long-term outcome by multivariate analysis: positive margin (p = 0.004), extrahepatic disease (p = 0.003), node-positive primary (p = 0.02), disease-free interval from primary to metastases <12 months (p = 0.03), number of hepatic tumors >1 (p = 0.0004), largest hepatic tumor >5 cm (p = 0.01), and carcinoembryonic antigen level >200 ng/ml (p = 0.01). When the last five of these criteria were used in a preoperative scoring system, assigning one point for each criterion, the total score was highly predictive of outcome (p < 0.0001). No patient with a score of 5 was a long-term survivor. CONCLUSION: Resection of hepatic colorectal metastases may produce long-term survival and cure. Long-term outcome can be predicted from five criteria that are readily available for all patients considered for resection. Patients with up to two criteria can have a favorable outcome. Patients with three, four, or five criteria should be considered for experimental adjuvant trials. Studies of preoperative staging techniques or of adjuvant therapies should consider using such a score for stratification of patients.

Adult↗
PubMed1999

[Variations of EGG in subjects under vestibular stimulation].

Objective. To investigate the patterns of electrogastrogram [correction of electrogastrogragm] (EGG) before, during and after vestibular stimulation. Method. 25 subjects were stimulated by Coriolis acceleration and 28 by Coriolis [correction of corolis] stimulation. Result. Dysrythmia of EGG and increase of tachygastria were recorded in all subjects during the stimulation. The period dominant frequency (PDF) of EGG shifted from 2.40-3.70 cpm to 3.70-10.00 cpm during Coriolis stimulus in subjects with nausea. Conclusion. It suggests that PDF could be a parameter in reflecting the level of motion sickness.

Acceleration↗
PubMed1992

Transcoronary chemical ablation of ventricular tachycardia.

Transcoronary chemical ablation of ventricular tachycardia was recently performed in one patient with refractory ventricular tachycardia in our hospital. The procedure was successful. The arrhythmia was cured and no recurrence occurred in a 24-month period. The clinical application and mechanism of transcoronary chemical ablation were discussed.

Adult↗
PubMed1992

Electrophysiologic follow-up in dogs receiving intracoronary ethyl alcohol injection.

96% ethyl alcohol was injected into a diagonal branch of the left anterior descending coronary artery of 10 out of 12 anesthetized dogs, and saline solution was injected in the remaining 2. After chest closure, the dogs were subjected to ambulatory monitoring (H) during days 1, 2, 3 and 7. The electrophysiologic study (EPS) and signal-averaged electrocardiography. (SA-ECG) were performed before the injection and again at day 7 after injection. H failed in one dog which died of ventricular fibrillation. In the other 9 dogs that received alcohol injection, H showed frequent ventricular premature and ventricular tachycardia (VT) after injection; six of the 9 dogs sustained VT, which was not inducible by EPS. VT was not found in 2 control dogs receiving saline solution injection. The SA-ECG showed no ventricular late potentials in dogs receiving alcohol injection. Post-ablation ventricular arrhythmia (including VT) occurred after intracoronary ethyl alcohol injection in all dogs. Arrhythmogenicity markedly declined during the first 3 days and almost completely disappeared on day 7 after ablation. There was no evidence in favor of reentry as the mechanism of these arrhythmias. Enhanced automaticity was considered as the mechanism for ventricular arrhythmia.

Animals↗
PubMed1991

Transcoronary ethanol ablation of experimental ventricular tachycardia after epicardial ice mapping and localizing.

Thirty-seven reproducible ventricular tachycardias (VTs) were induced in 19 dogs after the onset of myocardial infarction. The site of origin of VT was localized in 19 (59%) of 32 VTs by ice epicardial mapping. After 0.3-1.2 ml of 95% ethanol was injected into a small coronary artery supplying the arrhythmogenic area, VT was no longer inducible in 10 of 14 dogs. Intramyocardial ethanol (1-3 ml) was injected into the site of origin of VT in 9 dogs including 4 with VTs reinduced after intracoronary ethanol. Six of these VTs were not reinduced. Thus, the total efficacy rate was 84%. In 7 dogs, after injection of 0.4-1.2 ml (mean 0.5 ml) of 95% ethanol into a small normal coronary artery, the extent of the changes in ECG, CK-MB and pathology was found to be related to the size of myocardial damage and to the dose of ethanol. The smaller the dose of ethanol was given and the more distal the branch of coronary artery into which the ethanol was injected, the smaller the myocardial damage was. The data demonstrated that intracoronary or intramyocardial injection of ethanol may ablate the experimental VT induced by programmed heart stimulation in dogs after myocardial infarction, indicating that this approach may be useful and meaningful in some selected instances. However, it is necessary to limit the myocardial damage as far as possible.

Animals↗
PubMed1989

[Electrophysiologic effects of intravenous propafenone].

The electrophysiological effects of intravenous propafenone were studied with programmed electrical stimulation in 31 patients. Among them 29 cases with SVT (including WPW syndrome in 11, paroxysmal AF or Af in 3) and the other two cases were studied for other reasons. The results showed that: (1) Propafenone has significant effects on each part of the special conduction tissues of the heart as well as the accessory pathway. (2) It is an effective drug for treating AVNRT and the tachycardias associated with WPW syndrome. (3) There were no effects on sinus node function in all except one patient whose SNRT was prolonged to 2020 ms. (4) Neither blood pressure dropping nor other side effects were found during the studies.

Adolescent↗
PubMed1989

[Electrophysiologic study of concealed accessory A-V pathway].

The presence of concealed accessory A-V pathways (CAP) was demonstrated in 14 out of 18 (78%) patients with supraventricular tachycardia (SVT) and narrow QRS complexes. Such a high percentage of CAP mediated AVRT is a quite unique finding. The importance of a standard programmed electrical stimulation protocol in documenting CAP is emphasized. Careful atrial mapping and premature ventricular stimulation during SVT are very helpful for diagnosis and localization of CAP. We considered that a V-A interval of 75 ms or more on intracardiac electrogram or a R-P interval of 85 ms or more on esophageal electrogram is a good criterion for AVRT utilizing an accessory pathway.

Adolescent↗
PubMed1989

[Pacemaker syndrome: a report of 6 cases].

Six patients suspected to have "pacemaker syndrome" were studied with hemodynamic and electrophysiologic methods. Symptoms appeared after implantation of ventricular pacemaker (VVI). Mile symptoms such as dizziness and fatigue and severe symptom of heart failure were noted. The results of the study suggested that cardiac output decreases due to loss of atrial contribution to ventricular filling and also as a result of increase of systemic venous pressure. If the patient has V-A conduction, cardiac output will decrease further. Restoration of atrioventricular synchronization is essential in the treatment of the pacemaker syndrome.

Aged↗
PubMed1987

Intra-hisian block associated with unusual etiologies.

One hundred and sixty-nine patients underwent electrophysiologic study for atrioventricular block. Forty-five (27%) had intra-Hisian block. Four of these 45 patients had unusual etiologies: rheumatoid arthritis, cysticercosis cellulosae, Behcet's disease, and Takayasu aorto-arteritis. Their clinical and electrophysiologic features are described in detail.

Adult↗