Biomedical subjects
Publications and source records attributed to H Z Zheng.
Quantum computing is a quickly growing research field. This article introduces the basic concepts of quantum computing, recent developments in quantum searching, and decoherence in a possible quantum dot realization.
AIM: To Investigate the myocardial ultrastructure effects of SMT on the ischemia reperfusion injury (IRI) in the rat heart. METHODS: Eighteen Spraqua-Dawley rats were randomly divided into three groups: ischemia reperfusion group (IR), subjected to 60 min of o-cclusion and 20 min of reperfusion of the anterior descending branch of left coronary artery; IR + SMT group (SMT), given the selective iNOS inhibitor S-methylisothiourea sulfate (SMT, 5 mg/kg, i.v.) before reperfusion; control group (C), didn't occlude coronary artery after exposing heart and observed 80 min. Electrocardiogram (ECG) was recorded. Nitrite and nitrate content were measured in myocardium and blood serum. The changes of myocardial ultrastructure were observed with electron microscope. RESULTS: Ischemia reperfusion induced ST segment elevation and T waves inversion or tallness in ECG, damaged myocardial ultrastructure, increased nitrite and nitrate content in myocardium and blood serum after IR compared with before IR(P < 0.01). Administration of SMT improved the changes of ECG and the injury of myocardial ultrastructure. Nitrite and nitrate content of myocardium were lower than IR group (P < 0.05). The change of nitrite and nitrate level of blood serum in SMT group was nearly in C group. CONCLUSION: SMT can prevent myocardium injury from reperfusion following ischemia.
Changes of L-arginine/nitric oxide pathway in heart and of L arginine transport in erythrocytes and their relationship were investigated in spontaneously hypertensive rats (SHR). 12 and 16 weeks old SHR, 16 weeks old SHR with captopril treatment for 4 weeks and 16 weeks old Wistar-Kyoto (WKY) rats were used. L arginine transport of myocardial ventricular tissue and erythrocytes, total nitric oxide synthase (tNOS) activity, nitrite and nitrate (NO(2) + NO(3)) and cyclic GMP (cGMP) content in myocardium were measured. The result showed that in myocardial ventricular tissue of SHR L-arginine transport decreased significantly with V(max) of the high-affinity transport being decreased by 24.3% (P<0.05, 12W group), 36.4% (P<0.01, 16W group) as compared with WKY group. Michaelis constant (K(m)) of low affinity transport was significantly lower than that of WKY group. NO(2) + NO(3) and cGMP content were respectively decreased by 24.6%, 19.8% (P>0.05, P<0.05, 12W group), 52.5%, 60.4% (P<0.05, P<0.01, 16W group) and 14.8%, 23% (P>0.05, P<0.05, SHR+C group) as compared with WKY group. But the K(m) of L-arginine high-affinity transport and the V(max) of low affinity transport and tNOS activity were not significantly changed. In erythrocytes, the changes of L-arginine transport coincided with those of myocardial tissue. The V(max) had significant positive correlation with the V(max) of high-affinity transport in myocardial tissue, r=0.5606, P=0.01 and had negative correlation with left ventricular weight to body weight radio, r=0.6231,P<0.01. These results indicate that the activity of L-arginine/nitric oxide pathway inhibited in myocardial tissue of SHR. The correlation between the inhibitory degree of L-arginine/nitric oxide pathway and the degree of ventricular hypertrophy is negative. The changes of L-arginine transport in erythrocytes coincide with those in myocardium.
Ischemia reperfusion injury (IRI) model of rat heart was prepared by preperfusion for 15 min, then a suspension for 45 min and recycling reperfusion for 15 min with 30 ml KH buffer. The leakage of lactate dehydrogenase(LDH),protein, myoglobin and nitrite (NO2-) in the circular perfusion fluid were measured. Myocardial nitric oxide synthase(NOS) activity and L-arginine transport were observed. In the IR group, the leakage of LDH,protein, myoglobin and NO2- were increased respectively by 4.1,5.4,1 and 1.2 times(P<0.01) and NOS(tNOS, iNOS, cNOS) activity by 48.2%,43.2% and 52.1%,(P<0.01,respectively) as compared with the control group. L-arginine transport might be mediated by either high- or low-affinity transport system in cardiac tissue. In the IR group, L-arginine transport increased significantly with the V(max) being increased by 48% and 2 times respectively for the low-affinity and the high-affinity transport as compared with control. Michaelis constant (km) was decreased by 47.4% for low-affinity transport (P<0.05),but not significantly changed for the high-affinity transport. These results suggest that the increase of nitric oxide generation might result from the increased myocardial NOS activity and L-arginine transport during IRI.
The signal transduction pathways of the inhibitory effect of nitric oxide (NO) on endothelin (ET)-induced proliferation of vascular smooth muscle cells (VSMCs) were studied. 3H-thymidine (TdR) incorporation, mitogen-activated protein kinase (MAPK) activity and protein kinase C (PKC) activity of cultured VSMCs of rabbits thoracic aorta were measured in the presence of either NO precursor L-arginine (L-Arg) or NO donor 3-morpholino sydnonimine-hydrochloride (SIN-1), or ET-1 alone or with L-Arg or SIN-1. The results show: (1) ET-1 (10(-8) mol/L) significantly increased VSMCs 3H-TdR incorporation (5 times, P < 0.01), MAPK activity (4 times, P < 0.01) and PKC activity (3 times, P < 0.01), as compared with control. L-Arg or SIN-1 alone was without effect on 3H-TdR incorporation, MAPK activity and PKC activity. (2) When ET-1 and L-Arg (2, 5, 10 mmol/L) were simultaneously administered, 3H-TdR incorporation and activity of both MAPK and PKC were all significantly decreased in comparison with the ET group. (3) When ET-1 + SIN-1 (5, 10, 50 mumol/L), the effects coincide with those of the ET-1 + L-Arg groups. These findings indicate that NO inhibition of the signal transduction pathways of the ET-1-induced proliferation of VSMCs may be mediated by the inhibition of ET-1-induced activation of both PKC and MAPK.
Pre-eclampsia is an endothelial disorder and TNF-alpha has fundamental effects on endothelial cells by several means, including altering the balance between oxidant and anti-oxidant, changing the pattern of prostaglandin production and affecting expression of several cell surface components. To determine whether TNF-alpha mRNA expression is increased in pre-eclamptic patients, leucocytes from pre-eclamptic patients, normal pregnant women and normal non-pregnant women were studied for TNF-alpha expression using a quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) method. Using a model of 373A ABI Sequencer, TNF-alpha gene polymorphism was also analysed by GENESCAN and Genotyper software in order to explain the mechanism of abnormal TNF-alpha expression. Our results show that TNF-alpha mRNA expression is significantly elevated in pre-eclamptic patients compared with the other two control groups. The high expression of TNF-alpha may be associated with the TNF1 allele, whose frequency is markedly increased in pre-eclamptic patients. These observations are consistent with a major role for TNF-alpha in mediating endothelial disturbances, and suggest a key role for TNF-alpha in the development of pre-eclampsia.
Nine pairs of dogs were operated with head cross circulation and four pairs of dogs with brain cross circulation. Bleeding of formoral artery decreased the mean arterial pressure to 5.33 kPa and maintained for 30 min. In each pair of A dog 10% of total blood lose was infused intravenously by 7.5% NaCl solution (as test) or normal saline (as control), but B dog was not treated. The results showed that in the test group the arterial blood pressure recovered immediately in both A and B dogs and lasted for more than 60 min after infusion. The recovery value of systolic pressure was higher than diastolic pressure and pulse pressure increased. In the control group the blood pressure recovered slightly but of no statistical significance. There was no remarkable difference in heart rate between the two groups. A marked decrease in hematocrit appeared after bleeding and infusion, but there was no significant difference between the two groups (P > 0.05). Plasma sodium increased significantly after infusion in A dogs of the test group (P < 0.01), but the change in B dogs was the same in the control group. These results mentioned above indicate that the central nervous system plays important role on the mechanism of pressor response induced by infusing 7.5% NaCl solution in the hemorrhagic hypotension dog.
From October 1987 to May 1989, a total number of 527 women completed a total of 6,291 treatment cycles in 6 centers in China for the study of a triphasic oral contraceptive - Triquilar. The mean age of subjects was 30.21 +/- 2.84 years. There were 7 pregnancies during the study period. Among them, five were patient failures because of missed pill or incorrect intake; one had taken barbiturates along with Triquilar. Only one woman became pregnant in the 11th treatment cycle without any reason being found. In most cases, menstrual flow decreased and dysmenorrhea improved as treatment continued. Of the total treatment cycles, the incidence of missed withdrawal bleeding was 0.25%, spotting 0.97%, and breakthrough bleeding 0.48%. Nausea and vomiting was the most common side effect and accounted for 6.4% of the total treatment cycles. This was followed by breast tenderness (3.7%), dizziness (2.4%) and headache (1.6%). Most of the side effects occurred during the first few cycles and were alleviated later. By the end of one year, the total dropout was 64 cases. The reasons for discontinuing treatment were: pregnancy 1.33 (per hundred women), menstrual disturbances 0.76, side effects 3.80, other medical reasons 2.09, and personal reasons 4.18. The results confirm that Triquilar is an effective oral contraceptive with good cycle control and low incidence of side effects. No serious reaction has been reported. It has been well accepted by the Chinese women. However, due to the low dosage of steroids, it is of utmost importance to avoid errors in its use.(ABSTRACT TRUNCATED AT 250 WORDS)
Human peripheral blood lymphocytes were cultured in diffusion chamber in mice after short-term administration of gossypol acetate. The induced chromosomal aberrations of human target cells indiffusion chamber were used as indices of DNA damage. The results showed that the mean frequency of chromosomal aberration of the human lymphocytes in Gossypol-treated mice was slightly higher than that in the control group, but the difference between them was not statistically significant (p 0.05).
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A healthy normally intelligent man and his two daughters who had mild developmental delay and different malformations were determined to have an acrocentric supernumerary microchromosome (MC). The father and both daughters were noted to be mosaic for the MC, perhaps suggesting mitotic instability of the MC cell line with loss over time. The MC was negative staining on G-banding and showed absence of centromeric heterochromatin on C-banding. A centromere was identified with silver staining; no NORs were identified. The MC approximated the size of the short arm of the Y chromosome and showed cytologic behavior similar to that of a Y chromosome. H-Y antigen and Y-DNA gene probe studies failed to confirm a Yp origin.
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