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Biomedical subjects

J Han

Publications and source records attributed to J Han.

At least 415 records · Page 23Linked to original sources
PubMed1990

Birth number base and its application.

"This paper attempts to present the concept of 'birth number base' as a reflection of the fecundity of women, explain the methods of determining the base, and its application." The birth number base is defined as the number of births in a given year when the total fertility rate is one. The concept is applied to Chinese data from the 1 per 1,000 population survey of 1982 to project the number of births that will have to be prevented in the future if China is to reach its population targets.

Asia↗
PubMed1990

[Influence of microinjection of dynorphin antibody into periaqueductal gray (PAG) on analgesia induced by electroacupuncture of different frequencies in rats].

Previous studies have shown that 2 Hz but not 100 Hz electroacupuncture (EA) stimulation released beta-endorphin in PAG of the rat to induce analgesia. The present study was undertaken to see whether dynorphin plays a role in PAG in mediating analgesia induced by low and high frequency EA. Injection of affinity purified dynorphin antibody (1:350,000 in RIA titer) 1 microliter into PAG blocked 2 Hz EA analgesia almost completely, and 15 Hz EA analgesia partly, leaving 100 Hz EA analgesia intact. This blocking effect was totally disappeared when the antibody was diluted to 1/10 of its original concentration (1:35,000). Besides, injection of dynorphin into PAG through chronically implanted cannula showed no analgesic effect. The results suggest that the blockade of 2 Hz EA analgesia by high titer dynorphin antibody injected into PAG may have been the result of cross reactivity of the antibody to other opioid peptides (such as beta-endorphin, enkephalin, etc) released in the PAG area. The data also stress the importance of using antibodies of proper titer and concentration to exclude false positive or false negative conclusions in adopting the antibody microinjection techniques, as was repeatedly shown in the immunohistochemical studies.

Acupuncture Analgesia↗
PubMed1990

[Microanatomical relationships of the anterior inferior cerebellar artery and the facial nerve].

The microanatomical relationships between facial nerve and anterior inferior cerebellar artery were examined in 30 adult cadavers. Seventeen of the 60 arteries were situated ventrally to the facial nerve; 8 dorsally to the facial nerve root; 26 passed between the seventh and eighth cranial nerves; 9 round the seventh and eighth cranial nerves. Forty-one of the 60 nerves were in contact with the arteries. The significance of microanatomical relationships between the anterior inferior cerebellar artery and the facial nerve was discussed.

Arteries↗
PubMed1990

[Enkephelinase inhibitors acetorphan and SCH34826 potentiate the analgesic effect of low frequency electroacupuncture in rats].

Influence of two novel enkephelinase inhibitors, Acetorphan and SCH34826, on the effect of electroacupuncture analgesia (EAA) has been observed in rats. Administered Acetorphan (2.0-4.0 mg/kg, i.p.) or SCH34826 (30-100 mg/kg, p.o.) potentiated and prolonged the effect of 2 Hz EAA significantly in the nonresponder in which an evident analgesic effect can not be induced by 2 Hz electroacupuncture. This means that che non-responder of 2 Hz EAA can be converted into the responder with these two drugs. The non-responder of 100 Hz EAA, however, can not be changed into the responder with Acetorphan. These results again support our previous reports that enkephelin plays an important role in low frequency EAA. Meanwhile, this suggests us a probable route for potentiating acupuncture analgesia in clinical practice.

Acupuncture Analgesia↗
PubMed1990

[Pharmacokinetic study of sodium selenite in low-selenium rabbits].

Sodium selenite has been used for prevention and treatment of Keshan disease and Kaschin-Beck's disease. The efficacious dosage regimens of sodium selenite in low-Se human body have not been clear. A single iv or ig of sodium selenite 2.0 mg/kg was given to rabbits. Selenium in whole blood was determined fluorophotomerically. The concentration-time curve following a single iv of sodium selenite in rabbits was found to be of 3-compartment open model. The pharmacokinetic parameters were: T1/2 x 0.11 +/- 0.03 h, T1/2 alpha 6.8 +/- 2.8 h, T1/2 beta 215 +/- 35 h, Vc 0.50 +/- 0.07 L/kg, Cl 19 +/- 5 ml/(kg.h), AUC 146 +/- 26 mg.h/L. The concentration-time curve following a single ig of sodium selenite showed a pattern of 2-compartment open model. The parameters were: T1/2 kappa a 13 +/- 6 h, T1/2 alpha 3.6 +/- 1.9 h, T1/2 beta 338 +/- 107 h, Vc 2.9 +/- 1.3 L/kg, AUC 78 +/- 29 mg.h/L, Cl 27 +/- 11 ml/(kg.h). In low-Se rabbits the distribution in body was more rapid and more extensive, and the bioavailability was higher than that in normal-Se rabbits. Therefore, attention should be paid to the different levels of selenium during therapy with sodium selenite.

Animals↗
PubMed1989

Arrhythmogenic effects of mexiletine in infarcted Purkinje tissues.

The electrophysiologic effects of mexiletine on canine subendocardial Purkinje's fibers were examined 24 hours after a two-stage ligation of the left anterior descending coronary artery. Transmembrane potentials were recorded simultaneously in normal (NZ) and infarcted (IZ) zones before and during superfusion with mexiletine. Mexiletine (3, 6, and 9 mg/l) reduced the values of maximum diastolic potential (MDP), action potential amplitude (APA), and maximum rate of phase 0 depolarization (Vmax). The effective refractory period (ERP) was lengthened by the drug. These findings are consistent with the actions of class IB antiarrhythmic drugs. In 42% of the preparations examined, repetitive responses were induced at or near the ERP during superfusion with 3 mg/l mexiletine. These extra responses were no longer elicited during superfusion with 6 mg/l mexiletine. A mechanism for the origin of these reentrant-type arrhythmias based on the action of mexiletine is presented.

Animals↗
PubMed1989

[The clinical significance of serum creatine phosphokinase measurement in patients with chronic cor pulmonale].

The values obtained from the measurement of serum creatine phosphokinase (SCPK) in 70 cases of chronic cor pulmonale in exacerbation and 72 cases in remission were compared with the normal value as measured in 160 healthy adults at the same period. The results showed that the normal value of SCPK was 46.50 +/- 12.71 u/L in male, while 32.51 +/- 10.8 u/L in female. The differences of the values of SCPK in male and female are highly significant statistically (P less than 0.001). Although the values of SCPK were within normal limits (M +/- 2SD) in most patients with chronic cor pulmonale (72.38-84.10%) in this paper, the values of SCPK of some of them (13.60-22.36%) were higher than normal. But in a few of the patients in exacerbation (2.27-5.26%) the SCPK values were lower than normal. The increased activity of SCPK in patients with chronic cor pulmonale may be related to the vigorous movement of the respiratory muscles. While the level of SCPK decreased to extremely low degree may indicate that the respiratory muscles may be excessively fatigue. So we suggest that the levels of SCPK which are markedly higher or lower than normal could be served as an reference index for the excessive activity or fatigue of the respiratory muscles respectively in chronic cor pulmonale.

Adult↗
PubMed1988

Biochemical and molecular properties of cisplatin-resistant A2780 cells grown in folinic acid.

In this study, A2780 human ovarian carcinoma cells were grown in folinic acid in contrast to folic acid, and the molecular and biochemical properties of cisplatin-resistant A2780 cells were analyzed for changes in the dTMP synthase cycle. At concentrations of folinic acid that were optimal for cell growth (10(-8) M), the ED50 for cisplatin was 2.5 and 43 microM in the A2780S and A2780DDP cells, respectively. Resistance to cisplatin was associated with a 2-fold cross-resistance to 5-fluorodeoxyuridine and 5-fluorouracil as well as a 3-fold increase in both dTMP synthase activity and mRNA. The ED50 for methotrexate was similar in both A2780S and A2780DDP cells (1.2 microM). When both the A2780S and A2780DDP cells were grown in folinic acid, there was no significant difference in the level of dihydrofolate reductase activity. This data would suggest that cisplatin resistance is associated with changes in folate metabolism.

Cell Line↗
PubMed1988

Cinevideodensitometric analysis of the effect of coronary angioplasty on coronary stenotic dimensions.

The accuracy and reproducibility of caliper and cinevideodensitometric measurements of coronary stenotic dimensions were compared in radiographic phantom models and in coronary arteriograms of 28 patients undergoing coronary angioplasty. Projected, single-plane coronary cine frames were analyzed by a computer-assisted videodensitometric method, which measures stenotic cross-sectional area without assumptions about lesion geometry. The accuracy (2.4%) and precision (+/- 1.9%) of cinevideodensitometry for measuring percent area stenosis in Plexiglas models of eccentric stenotic lesions was superior to the accuracy (24.7%) and precision (+/- 5.4%) of caliper measurements. Interobserver variability was significantly (p less than 0.05) better for cinevideodensitometric (r = 0.98; SEE = 6.4%) than for caliper measurements (r = 0.87; SEE = 13.1%). After angioplasty, percent diameter stenosis measured by calipers fell from 70 +/- 12% to 30 +/- 15%. Mean percent area reduction measured by cinevideodensitometry fell from 89.1 +/- 8% to 40.1 +/- 22% and stenotic area increased five-fold, from 0.59 +/- 0.5 to 3.47 +/- 1.6 mm2. Pre and post PTCA gradients did not correlate with lesion dimensions. Cinevideodensitometric measurements of absolute stenotic dimensions were more reproducible than relative measurements expressed as a percentage, due to the tapered caliber of normal arterial segments. Thus, cinevideodensitometric measurements were more accurate and reproducible than caliper measurements. The angiographic effects of coronary angioplasty are best measured by cinevideodensitometry, because residual lesions post PTCA are often eccentric, have indistinct margins, and are better characterized by changes in area than by changes in diameter.

Angioplasty, Balloon↗
PubMed1988

Traditional Chinese medicine and the search for new antineoplastic drugs.

The experience of traditional Chinese medicine affords a valuable approach in the search for new antineoplastic drugs as illustrated by indirubin from Dang Gui Lu Hui Wan, irisquinone from Iris lactea pallasii and Zhuling polysaccharide from Polyporus umbellata. The application of chemotaxonomic principles to related species of those plants used in folk medicine has also provided an approach which can be used successfully for the development of new drugs. The studies of Cephalotaxus hainanesis and Camptotheca accuminata provide two typical examples in this regard. One must be aware that the experience of traditional Chinese medicine cannot be used without elaborate efforts in many cases. For example, the ancient Chinese ideograph for spleen does not mean spleen in the modern sense, instead it refers to the entire gastrointestinal system. Similarly, the ancient ideograph for kidney does not mean kidney in the modern sense, and can mean the entire endocrine system. Therefore, for the reasonable utilization of traditional Chinese medicine, one must be familiar with its basic concepts and terminology. In addition, one must bear in mind that the term "tumor" in folk medicine is applied to a very wide range of pathological manifestations which sometimes have no relation to the various forms of neoplasia. It is important for drugs and treatments to be analyzed carefully in modern terms to eliminate the false and to utilize the true information. Only in such a way can the experience of traditional medicine be integrated into modern medicine and make its contribution in the advancement of health care in the world.

Animals↗
PubMed1987

Evaluation of a cinevideodensitometric method for measuring vessel dimensions from digitized angiograms.

A cinevideodensitometric method for measuring the dimensions of small vessels by computer analysis of digitized cineangiograms was developed and validated in radiographic phantom models. With this method, which is based on full-width-at-half-maximum analysis of videodensitometric profile curves, the diameters of contrast-filled plexiglass cylinders ranging from 1.78 mm to 4.14 mm in diameter were measured to within 2% mean error. The theoretical basis for this method of cinevideodensitometric analysis is provided.

Angiography↗
PubMed1986

Effects of tocainide on Purkinje fibers from normal and infarcted ventricular tissues.

The left anterior descending coronary artery was occluded in anesthetized dogs. Dogs were sacrificed after 24 hours and the experimental preparations, which included both normal and infarcted tissues, were dissected from the left ventricles. Effects of tocainide in concentrations of 15-40 mg/l on action potentials of Purkinje fibers from normal and infarcted zones were studied using conventional microelectrode techniques. In the normal zone cells, tocainide superfusion produced a significant decrease in maximum diastolic potential, action potential amplitude, action potential duration to 50% and 90% repolarization and the rate of phase O depolarization, and no significant change in effective and functional refractory periods. In the infarct zone cells, it produced a significant decrease in action potential amplitude and the rate of phase O depolarization, a significant increase in effective and functional refractory periods, and no significant changes in the other parameters. The unequal actions of tocainide resulted in selective depression of maximum diastolic potential and action potential duration to 50% repolarization in the normal cells only, reducing the disparity in these parameters between normal and infarcted tissues. Tocainide increased the refractoriness (ratio of effective refractory period to action potential duration) in both cell types but this change was greater in the infarct zone. This decreased disparity of membrane potential and repolarization combined with increased refractoriness may help to block the arrhythmias observed in infarcted preparations following closely coupled stimuli.

Animals↗
PubMed1986

Progression of coronary atherosclerotic disease assessed by cinevideodensitometry: relation to clinical risk factors.

Progression of coronary artery stenosis was measured using a quantitative, computer-assisted cinevideodensitometric method in 144 arterial segments in 44 subjects undergoing coronary arteriography on two separate occasions at least 6 months apart. Projected coronary arteriograms were digitized into 512 X 512 pixel mode and percent stenosis was calculated by comparing background-corrected videodensitometric values over stenotic and normal segments. Subjects underwent repeat coronary arteriography because of worsening symptoms of angina or heart failure; subjects with renal failure, coronary artery bypass grafts or cardiac transplant were excluded. Clinical variables determined at the time of the first arteriogram included age, sex, serum cholesterol, systolic blood pressure and presence or absence of cigarette smoking, diabetes mellitus and left ventricular hypertrophy. The mean interval between arteriograms was 29.3 months. Overall progression of coronary stenosis was observed in 40 of the 44 subjects; the mean progression at 24 months was 39% (90% confidence interval, 33 to 45%) and at 36 months was 48% (40 to 56%). The degree of overall progression was related to the length of time between arteriograms (F = 5.81, p less than 0.05) and to serum cholesterol level (F = 4.37, p less than 0.05). These data indicate that using an accurate, quantitative method, it is possible to measure progression of coronary artery atherosclerosis within 2 to 3 years of the initial arteriogram. Serum cholesterol appears to be an important determinant of disease progression.

Angiography↗
PubMed1986

Effect of coronary stenotic lesions on regional myocardial blood flow at rest.

To determine the effect of atherosclerotic coronary lesions on myocardial blood flow in patients at rest, regional myocardial blood flow was measured distal to stenotic lesions in 29 patients with isolated proximal lesions of the left anterior descending artery. Severity of coronary stenosis was measured by computer-assisted cinevideodensitometric analysis of digitized coronary arteriograms. Regional myocardial blood flow was measured from the clearance rate of intracoronary 133Xe injected into the left main coronary artery and recorded with a multicrystal scintillation camera. In 21 patients with stenotic lesions ranging from 19% to 84% area reduction, distal regional myocardial blood flow was normal. In all eight patients with reduced regional myocardial blood flow distal to left anterior descending lesions, the minimum area of each stenotic lesion was less 0.80 mm2 (mean 0.34 +/- 0.2 mm2), minimum calculated diameter was less than 1 mm (mean 0.59 +/- 0.3 mm), and percent stenosis, based on the reduction in cross-sectional area, was greater than 85% (mean 94 +/- 4%). For all patients, distal flow, expressed as a fraction of normal flow, correlated with the lesion cross-sectional area (r = .84), minimum luminal diameter (r = .84), and percent area stenosis (r = -.70). Thus, resting myocardial blood flow distal to stenotic lesions of the proximal coronary arteries remains normal until the degree of narrowing is severe. The dimensions observed for critical coronary stenotic lesions correlate well with theoretical predictions based on fluid mechanics and with experimental preparations in laboratory animals.

Cineangiography↗