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Biomedical subjects

M Z Chen

Publications and source records attributed to M Z Chen.

At least 37 records · Page 2Linked to original sources
PubMed1991

[Radioligand assay of beta adrenoceptors in lymphocytes isolated from rat spleen].

[3H]Dihydroalprenolol ([3H]DHA) was used to label beta-adrenoceptors in intact lymphocytes isolated from rat spleen. The binding conditions were investigated by the methods of L9 (3(4)) orthogonal analysis, the results showed the optimum binding conditions were pH 7.7, 1 x 10(8) lymphocytes.ml-1 and 10 min at 25 degrees C for incubation. On these conditions the [3H]DHA binding to beta-adrenoceptors was rapid (T1/2 2 min) and readily reversed by propranolol 1 mmol.L-1 (T1/2 4 min). [3H]DHA saturation experiments indicated a single class of site with a KD of 7.2 +/- 2.2 nmol.L-1 and Bmax of 81 +/- 28 fmol/10(7) lymphocytes (n = 3). Computer analysis of competition experiments with isoproterenol and epinephrine revealed two classes of sites. One site had high affinity for the [3H]DHA and comprised 60 +/- 5% of the total number of sites, whereas the other site had a lower affinity. The affinity of the high affinity site was about 3 orders of magnitude higher than that of the lower affinity site.

Animals↗
PubMed1991

[Antiinflammatory drugs inhibit the elevation of plasma CGRP concentration in endotoxin shock in rats].

In the present study, we observed the effects of indomethacin, ibuprofen, naloxone and morphine on plasma CGRP concentration 3 h after endotoxin shock in conscious rats. The results showed that indomethacin, ibuprofen and naloxone significantly inhibited the elevation of plasma CGRP concentration as well as reduced the lesion in the intestine during endotoxin shock. However, morphine had no significant effect. The data are consistent with our hypothesis that prostaglandin, as one of the inflammatory mediators which increase in shock may be an important endogenous factor for triggering the CGRP release during endotoxin shock.

Animals↗
PubMed1990

[Effects of thyroxine on IgM production and beta-adrenergic receptor on lymphocyte in mice].

The effects of thyroxine (L-T4) on the IgM production of splenocytes in mice induced by sheep red blood cell (SRBC) were investigated by means of spectrophotometry of quantitative hemolysis (QHS). The maximum binding site number (Bmax) and affinity (Kd) of beta-adrenergic receptors (beta-Adr. R.) on splenic lymphocytes of mice under the different thyroid functional status during immune response were determined by radio-ligand combination method. The IgM production and Bmax of beta- Adr. R. of splenic lymphocytes were increased in "hyperthyroid mice" and decreased in "hypothyroid mice" as compared with the control (P less than 0.01) during the 3rd to 5th day after immunization with SRBC, but affinity of beta-Adr. R. was not changed (P greater than 0.05). It is suggested that L-T4 could increase the IgM production in lymphocytes induced by SRBC in mice. The underlying mechanism seems to involve an increasing Bmax of beta-Adr. R. on the immune cell, thus enhancing its sensitivity to catecholamine.

Animals↗
PubMed1989

Calcitonin gene-related peptide in the pathogenesis and treatment of hypertension.

The present study demonstrated that the plasma calcitonin gene-related peptide (CGRP) concentration was lower but the CGRP content of abdominal aorta was higher in spontaneously hypertensive rats (SHR) than in normotensive rats (WKY), using specific CGRP radioimmunoassay (P less than 0.01). In eighteen patients with essential hypertension, the concentration of plasma CGRP was also much lower than that of normal subjects, suggesting that a decreased release of arterial CGRP might be a part of the pathogenesis of essential hypertension. In SHR, a significant decrease in blood pressure was found following intravenous injection of 2.5 micrograms/kg of CGRP; similarly, in seven patients with essential hypertension intravenous injection of CGRP (50 micrograms) could induce a significant hypotensive effect. These data suggest that CGRP is a new potential drug for the treatment of essential hypertension.

Adult↗
PubMed1989

Effects of pulse excimer laser irradiation on the human left ventricular wall.

This study was to assess the potential application of excimer lasers in the ablation of myocardium in vitro for the treatment of constant ventricular tachycardia or hypertrophic cardiomyopathy. A fresh human heart and EMG model 103 XeCl pulse excimer laser machine were used. The pulse repetition rate varied from 1 to 7 Hz. Irradiation directly on the left endocardial and epicardial walls lasted for 10 seconds and was repeated 3 times, creating 3 craters. The histological changes were examined by light microscope. Results showed very close relations between the depth or volume of vaporized craters and the pulse repetition rate on the endocardial (r = 0.9674, P less than 0.001 and r = 0.8962, P less than 0.01, respectively) and epicardial walls (r = 0.9602, P less than 0.001 and r = 0.9612, P less than 0.001, respectively). A sharp, clear border without debris or coagulating necrosis was seen under the microscope. We concluded that the pulse excimer laser, differing from Ar+ or Nd:YAG lasers, might be a powerful tool for manipulating the human ventricular wall, but more work needs to be done before it can be widely applied in the treatment of cardiovascular disease.

Chlorides↗
PubMed1989

[Percutaneous coronary laser angioplasty in a patient with chronic total obstruction of the right coronary artery].

Percutaneous coronary laser angioplasty was performed in one patient with total occlusion of right coronary artery without further balloon angioplasty in the ablated site. First of all, we used intracoronary urokinase in a total amount of 60,000 units that resulted in opening the total occluded right coronary artery to provide a passage of guidewire of laser catheter. Then a laser catheter was inserted through the guide catheter and its metal cap was in contact with the atherosclerotic lesion. The Nd:YAG laser was activated to vaporize the lesion (total energies of 54 J). Finally, the degree of residual stenosis was reduced from 95% to 20%. Percutaneous coronary laser angioplasty is a new method in treating coronary artery disease, yet it is still in its infant stage and further work is needed to develop this technological procedure.

Adult↗
PubMed1989

Clinical application of coronary laser angioplasty during coronary bypass surgery.

Laser irradiation offers the potential of removing atherosclerotic plaques from blood vessels. We used the Nd:YAG laser to treat coronary atherosclerotic obstruction in patients undergoing coronary bypass. Of the 7 patients treated, all were successfully recanalized without damage to the artery wall (a mild hematoma developed in 1 case), and follow-up examination showed patency 4 months after operation. We conclude that Nd:YAG laser shows promise for the treatment of atherosclerotic obstructions, but more study is needed before wide clinical application is justified.

Adult↗