Biomedical subjects

H Y Zhao

Publications and source records attributed to H Y Zhao.

At least 37 records · Page 2Linked to original sources

PubMed1994

Effects of isoprenaline, phenylephrine on heart and influence of nifedipine on these effects.

In a perfused isovolumetrically contracting rat heart model, the effects of isoprenaline (IPN) and phenylephrine (PE) on myocardial contraction and relaxation were investigated, and the influence of nifedipine on these effects was studied. Both IPN and PE increased the myocardial contraction and improved its relaxation, but some differences existed. Nifedipine (10 nmol/L) substantially inhibited the PE-mediated inotropic effect, but in case of IPN-mediated inotropic ones, it did not. It was assumed that there may be various types of slow channels, one was activated by IPN, and the other, by PE.

Animals↗

PubMed1994

Hepatitis C virus RNA and antibodies among blood donors in Beijing.

Blood units from voluntary as well as commercial donors in Beijing, China, were tested for hepatitis C virus RNA and antibodies, and for serological markers of hepatitis B virus infection. HCV RNA was detected less frequently in 1909 voluntary donors (5 (0.3%)), than in 1017 commercial donors (58 (5.7%)) (p < 0.001). Antibody to hepatitis C virus was detected by the second-generation enzyme immunoassay in 55 (87%) of 63 blood units with viremia. Evidence of present or past infection with hepatitis B virus was common both in voluntary (43.9%) and commercial (46.4%) donors. There were eight (13%) sera with HCV-RNA in which hepatitis C virus antibodies were not detectable by second-generation enzyme immunoassay. Of 63 HCV-RNA samples from donors, 33 (52%) were of genotype II, 18 (29%) of III and one (2%) of II + III. HCV-RNA in the remaining 11 (17%) were not classifiable into any of the genotypes I, II, III, IV and V. Genotype II was more frequent in viremic donors with elevated alanine aminotransferase levels (13/18 or 72%) than in those with normal levels (20/45 or 44%). These results indicate a low prevalence of hepatitis C virus infection in the general population in Beijing, and the limitations of identifying sera with viremia by second-generation enzyme immunoassay.

Adult↗

PubMed1994

Symptomatic hemodynamic and hormonal effects of intravenous captopril in patients with heart failure.

Since only oral preparations of captopril are clinically available, intravenous captopril was studied in 10 patients with mild heart failure and in 20 severe. The results showed that intravenous captopril may rapidly reduce cardiac preload and afterload, increase cardiac output, inhibit renin-angiotensin-aldosterone system, and depress plasma levels of catecholamine. After captopril infusion, a rapid symptomatic improvement occurred and the infusion could be well tolerated in patients with acute or severe heart failure. In addition, reversing hyponatremia and hypokalemia or improving azotemia may benefit the patients with acute or severe heart failure.

Adult↗

PubMed1994

Prevention of atherosclerotic arterial stenosis and restenosis after angioplasty with Andrographis paniculata nees and fish oil. Experimental studies of effects and mechanisms.

Restenosis rate after coronary angioplasty has been up to 30%-40%. To solve this problem, we studied the effects of Andrographis Paniculata Nees (APN) and fish oil (FO, omega 3 polyunsaturated fatty acids over 70%) on atherosclerotic stenosis and restenosis after experimental angioplasty and the relevant mechanisms of APN and FO. Preliminary results showed that APN can significantly alleviate atherosclerotic iliac artery stenosis induced by both deendothelialization and high cholesterol diet (HCD) and restenosis following angioplasty in rabbits. FO showed the same but milder effects than APN did. Both APN and FO significantly inhibited blood monocytes to secrete growth factors in vivo. Ca(++)-ATPase activity of cell membrane of atherosclerotic rabbits was significantly decreased, while APN or FO, especially the former alleviated this reduction. Refined extract of APN significantly decreased in vitro resting platelet [Ca++]i and in vivo the resting and thrombin-stimulated platelet [Ca++]i after oral administration of APN for 2 weeks. APN significantly inhibited cell growth or DNA synthesis in dose-dependent manner. In conclusion because of the mechanisms described above, APN can alleviate atherosclerotic artery stenosis induced by both deendothelialization and HCD as well as lower restenosis rate after experimental angioplasty. The effects of APN are evidently superior to those of FO.

Angioplasty, Balloon↗

PubMed1993

An experimental study and clinical pilot trials on yttrium-90 glass microspheres through the hepatic artery for treatment of primary liver cancer.

BACKGROUND: Yttrium-90 (90-Y) glass microsphere is a new kind of radiation microsphere for internal radiation therapy of primary liver cancer (PLC). The study was carried out by administration of 35 microns nondegradable 90-Y glass microsphere through the hepatic artery for treatment of PLC. METHODS: Six rabbits were injected with 185-1480 megabecquerels (MBq) of 90-Y glass microspheres, and three rabbits were injected with 35-300 mg of 89-Y glass microspheres for the toxic test. Eighteen patients received 2442-5550 MBq of 90-Y glass microspheres for the treatment of PLC. Whole blood counts, liver function, and imaging examination were performed. Pathologic examinations were performed on all rabbits. RESULTS: All rabbits were apparently well after absorbing 114.1-845.2 Gy 90-Y glass microspheres in the liver but showed transient degeneration of hepatocytes and portal fibrosis histologically. The mean absorbed dose in liver tissue of patients with PLC was 30.33 Gy, whereas that in tumor tissue was 88 Gy and the highest in tumor tissue, 186.36 Gy. The mean tumor:liver tissue ratio was 3:1; the highest, 14:1. Fourteen patients were still alive after half a year's follow-up and 6 of these 14 were still alive after 1 year. CONCLUSIONS: The rabbits could tolerate up to eight-fold of the upper limit of clinical dose (100 Gy). Good responses to the radiation therapy of 90-Y glass microspheres in patients with localized and hypervascular or vascular mass were achieved. Contraindications for the therapy were presence of massive hepatic arterioportal shunt and cancer emboli in the main portal vein. It is safe and applicable to deliver 90-Y glass microspheres in large doses through the hepatic artery for internal radiation treatment of PLC.

Adult↗

PubMed1993

Effects of captopril on platelet cytosolic free Ca2+ concentrations and on suppression of cell proliferation in culture.

In order to investigate the feasibility of angiotensin converting enzyme inhibitors (ACEIs) in preventing the development of atherosclerosis and restenosis after coronary angioplasty and to study their mechanisms, we measured the platelet cytosolic free Ca2+ concentration ([Ca2+]i) and observed the effects of captopril on platelet [Ca2+]i in rabbits and also observed the inhibitive action on fibroblast proliferation in culture. The results showed that resting platelet [Ca2+]i,ADP- or thrombin-stimulated platelet elevation amplitude after administration of captopril (12.5 mg, twice daily) for 15 days were significantly reduced in comparison with those before administration. And captopril also significantly inhibited fibroblast proliferation or reduced 3H-thymidine (3H-TdR) incorporation in culture in a dose-dependent manner. These findings suggest that ACEIs are promising drugs to reduce restenosis incidence after coronary angioplasty and to prevent atherosclerosis as well as provide a new explanation for their effects of suppressing cell proliferation.

Animals↗

PubMed1993

Experimental studies on prevention of atherosclerotic arterial stenosis and restenosis after angioplasty with Andrographis Paniculata Nees and fish oil.

In order to search for effective drugs to reduce restenosis incidence after coronary angioplasty, we studied the effects of a Chinese herb, extract of Andrographis Paniculata Nees (APN), and Fish Oil (FO) on atherosclerotic stenosis and restenosis after experimental angioplasty. Preliminary results showed that APN can significantly alleviate atherosclerotic iliac artery stenosis induced by both deendothelialization and high cholesterol diet (control group, stenosis incidence 100%, stenotic severe degree 60.53 +/- 31.03%, of which 30% arteries (6) are total occlusion; FO group: stenotic incidence and severe degree are 77% and 53.00 +/- 21.17%, respectively, and in APN group they are 70% and 25.39 +/- 10.52%, respectively, P < 0.01), and follow-up angiography 4 weeks after angioplasty showed that dilated iliac arteries in control group all had severe restenosis, but in APN group no or only mild restenosis occurs, and in FO group restenosis is as severe as stenotic degree prior to angioplasty. These preliminary results suggest that APN and FO can significantly alleviate stenosis induced by deendothelialization and high cholesterol diet and restenosis after angioplasty, while the former has a more marked effect. The above findings lead the authors to conclude that APN may play an important role in preventing restenosis after coronary angioplasty, but FO may be useful in reducing the extent of of restenosis after coronary angioplasty.

Angioplasty, Balloon↗

PubMed1993

[A clinical study of intravenous captopril in heart failure].

A clinical study of intravenous captopril was performed in 10 patients with mild heart failure and 20 with severe heart failure. The results indicated that intravenous captopril may rapidly reduce cardiac preload and afterload, increase cardiac output, inhibit renin system activity and decrease plasma level of catecholamine. A short period of treatment with intravenous captopril may produce a rapid symptomatic improvement in patients with acute or severe heart failure. There was a good tolerance with the therapy.

Adult↗

PubMed1993

Yttrium-90 glass microspheres injected via the portal vein. An experimental study.

Nondegradable glass microspheres (35 mu) were injected into the portal vein for toxicity test in 15 rabbits. In 10 animals the microspheres were loaded with 90Y, giving liver absorbed doses between 24.6 and 437.4 Gy, and in 5 with 89Y (control group). The total amount of microspheres injected in each animal varied between 35 and 140 mg. The rabbits in the experimental group tolerated the effect of radioembolization in a dose 4 times higher than the upper limit of the clinical dose (100 Gy). After injection of 90Y glass microspheres into the portal vein of rats with diethylnitrosamine (DEN)-induced hepatic carcinoma, the microspheres, in addition to the liver parenchyma, accumulated in central and peripheral parts of the cancer nodules, causing necrosis. The internal radiation therapy of 90Y glass microspheres delivered via the portal vein may be an effective nonsurgical method for the treatment of liver cancer, especially in small nodules.

Animals↗

PubMed1991

Experiences in intravenous urokinase treatment of 100 acute myocardial infarction patients.

From 1980 to 1990 we treated 100 cases of AMI with i.v. urokinase (UK). According to the way of management and the dosage administered all these cases were divided into three groups: first stage of small dosage, second stage of trial big dosage, and third stage of comprehensive dosage. 36 patients of the first stage were treated with small dosage, 1-20,000 U b.i.d. for 1 week. 75% of the UK-treated and only 17% of the control group obtained relief of pain. Decrease of elevated ST reaching base line was 50 vs 8%, and FDP increased in 94%. 22 patients of the second stage were undergoing trial of big dosage. They were subdivided into larger dosage (more than 800,000 U) and smaller dosage (less than 300,000 U) groups. From the larger dosage group, 2 patients showed definite sign of recanalization, but unexpectedly 2 patients died of cardiac rupture. Since the recanalization rate of larger dosage group was 42.9%, but no case showed sign of recanalization in smaller dosage group, we are of the opinion that the dose of 800,000 U is rational for patients with symptoms' onset less than 3 h. Cardiac rupture was thought to be mostly due to reperfusion injury. Thus we designed the third stage of comprehensive dosage of UK. In this stage we used different dosage of UK and different ways of administration in 52 patients, based on the different symptoms' onset, so as to bring the effect of UK in full play. The aim of using UK is chiefly fibrinolysis as well as improvement of blood viscosity.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1991

Antithrombotic effects of Andrographis paniculata nees in preventing myocardial infarction.

In 16 dogs the endothelium of the left anterior descending coronary artery was injured mechanically. Then a copper wire was inserted into the lumen as a choke of flow and the vessel was slightly compressed from outside by a constrictor. Eight dogs had been treated beforehand with a preparation of flavone extracted from the root of the Chinese medicinal herb Andrographis paniculata (TFAP). In the control group, saline solution was given, the epicardially recorded ST segment started to elevate within 15 minutes, the platelet aggregation rate and the plasma levels of TXB2 increased rapidly, whereas the level of 6-k-PGF1 alpha remained stable. Platelet cGMP rose continuously; however, platelet cAMP rose only at 60 minutes. Histological findings confirmed the occurrence of arterial thrombus and myocardial necrosis. Contrariwise, in the pretreated group there was no elevation of the ST segment, plasma 6-k-PGF1 alpha and platelet cAMP were increased, the production of TXB2 and aggregation of platelets were inhibited, and no thrombus or myocardial infarction was induced. All data suggest that TFAP might promote the synthesis of PGI2, inhibit the production of TXA2, stimulate the synthesis of cAMP in platelets, impede aggregation of platelets, and thereby prevent the formation of thrombi as well as the development of myocardial infarction.

6-Ketoprostaglandin F1 alpha↗

PubMed1990

Protective effects of andrographis paniculata nees on post-infarction myocardium in experimental dogs.

One hour after the development of myocardial infarction by formation of thrombus, watery extract of Andrographis paniculata Nees (APN) was injected intravenously to 7 dogs for observing the protective effect of this drug on ischemic myocardium, 6 dogs served as control group. In the treated group PGI2 increased remarkably, synthesis of TXA2 was inhibited, cAMP in platelets was elevated, CK-MB peak was lowered and appeared earlier, ELT was shortened, release of platelet beta-GT was decreased, platelet maximum aggregation rate was inhibited, the size of ischemic area recorded by epicardial ECG was reduced, the amplitude of ST segment elevation was lower than that in the control group, Q wave appeared in only one dog. Pathologically, the myocardial structure surrounding the initially appearing ischemic area, i.e, the reversibly damaged area, became relatively normal, while the degree of myocardial degeneration and necrosis in the central part of the ischemic area was mild. These data suggest that APN may limit the expansion of ischemic focus, exert marked protective effect on reversibly ischemic myocardium and demonstrate a weak fibrinolytic action.

Animals↗

PubMed1990

Effect of Astragulas membranaceus on natural killer cell activity and induction of alpha- and gamma-interferon in patients with Coxsackie B viral myocarditis.

The patients suffering from Coxsackie B viral myocarditis with depressed natural killer (NK) activity were treated with Astragulas membranaceus (AM) intramuscularly for 3-4 months. After the treatment, the NK activity was increased significantly from 11.5 +/- 11.9% before therapy to 44.9 +/- 15.0%. Another 6 patients of Coxsackie B viral myocarditis with depressed NK activity were treated with conventional therapy. The NK activity remained unchanged in 12.9 +/- 6%. The general condition and symptoms improved in all patients with AM therapy, while the titers of neutralizing antibody remained at the same level. Two days after AM treatment, the mean titers of alpha- and gamma-interferon (IFN) markedly increased in comparison with those before therapy and 3 weeks after AM therapy in 16 patients with Coxsackie B viral myocarditis, with left ventricular ejection fraction (LVEF) less than 65% and/or weak ventricular wall motion assayed by radionuclide angiocardiography. Whereas, in 12 patients treated with conventional therapy, there was no statistical difference among the results before and 2 days and 3 weeks after treatment. The results indicate that AM could partly regulate the lost of control of cellular immunity in patients with viral myocarditis.

Coxsackievirus Infections↗

PubMed1989

Experimental and clinical study of catecholamine-induced hypokalemia in acute myocardial infarction.

Adrenaline infusion to 8 rabbits led to remarkable dose-dependent hypokalemia; 2 of them died of ventricular arrhythmia (VA) with severe hypokalemia. In 6 rabbits with i.v. propranolol beforehand, no hypokalemia occurred after adrenaline infusion. Plasma catecholamines (CA) in 26 patients with AMI were greatly elevated at admission, 73% of relative hypokalemia (plasma potassium decreased to greater than or equal to 0.3 mmol/L) and a significant lowering of intraerythrocytic rate of Na/K were noted. These findings were inversely correlated with adrenaline. According to the multivariate analysis, both high level of plasma adrenaline and hypokalemia were responsible for VA in early AMI. The mechanism of CA-induced hypokalemia and its implications in AMI were discussed in detail.

Aged↗

PubMed1989

[Effect of muskrat on the cardiovascular system in anesthetized dogs].

Muskrat and musk are secretions from the fragrant glands of male adult musk-rat (Ondatra zibethica) and musk-deer respectively. In this paper, the pharmacological effects of muskrat and musk are studied. The result shows that a dose of 24 mg/kg iv of muskrat or musk can decrease the HR, mAP, LVP, LVdp/dt max and TPR in anesthetized dogs. But muskrat has an effect of reducing MHO while musk has not. In addition, an injection of 120 mg/kg of muskrat or musk endures hypoxia in mice. But this function of muskrat was weaker than that of musk.

Animals↗

PubMed1989

Radioimmunotherapy for hepatocellular carcinoma (HCC) using 131I-anti HCC isoferritin IgG: preliminary results of experimental and clinical studies.

Based on radioimmunoimaging for HCC using 131I-anti HCC isoferritin IgG, the experimental and clinical studies on radioimmunotherapy for HCC were reported. Thirty-six nude mice bearing human HCC were used for the study of labeled IgG, pure 131NaI and pure IgG. In the labeled IgG group, the tumor inhibition rate was significantly higher than that in other groups (81%, 60%, and 18%, respectively, p less than 0.05). The tumor cell DNA analysis showed the tumor cell was inhibited in the S stage of the cell cycle. Twenty pathologically proven unresectable HCC patient were treated by 131I-antihuman HCC isoferritin IgG 20-55mCi monthly for 1-3 times (via hepatic arterial catheter or intravenously). The short-term response was promising, a decline in AFP level and shrinkage of tumor were observed in 80% (12/15) and 65% (13/20) of patients respectively. Sequence resection was successful in five patients (5/20) after radioimmunotherapy. No marked toxic effects were noted in our limited experience, but some problems remain to be discussed.

Adult↗

PubMed1989

[The findings of radionuclide angiocardiography in acute viral myocarditis].

Left ventricular function, both systolic and diastolic, was examined in 16 normal subjects and 62 patients of acute viral myocarditis with radionuclide angiocardiography. The results of patients as compared with those of normal showed that left ventricular ejection fraction, the peak ejection rate, the peak filling rate, the relative stroke volume and the relative cardiac output were lower (P less than 0.01 - 0.05). The phase angle from phase analysis was wider (P less than 0.01). Hypokinesia was noted by the observation of left ventricular wall motion 57 of 62 cases correlated well relative with the reduction left ventricular ejection fraction. Hypokinesia of left ventricular wall motion seems to be a more sensitive index than decrease of left ventricular ejection fraction for the diagnosis of acute viral myocarditis.

Adolescent↗

PubMed1989

Study on experimental model of coronary artery thrombogenesis and acute myocardial infarction: changes in epicardial ECG, platelet function and biochemistry, and pathology.

A model was produced for formation of coronary artery thrombosis and development of acute myocardial infarction (AMI) in experimental dogs (n = 8) by injuring endothelium of coronary artery with a steel wire, inserting a copper wire into the lumen, and producing local stenosis with a constrictor. The results showed that ST segment of epicardial ECG began to elevate 15-30 min after handling the coronary artery, platelets aggregation rate and plasma TXB2 increased rapidly, plasma 6-k-PGF1 alpha did not change, platelets cGMP rose continuously, while platelets cAMP rose only at 60 min after handling the coronary artery. Histological findings confirmed the occurrence of artery thrombus and myocardial necrosis. The model may be helpful in investigating the whole process of activation of platelet, thrombogenesis and development of AMI, with the changes in biochemistry, structure, pathophsiology and ECG monitored during the period.

Animals↗