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Biomedical subjects

Z C Liu

Publications and source records attributed to Z C Liu.

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

[Effect of acupuncture and moxibustion on antiobesity in the variation of plasma cyclic nucleotide and the function of vegetative nervous system].

The authors observed the changes of the obesity index, lipid index, the equilibrium indices of the vegetative nervous system (Y value) and the plasma cAMP of 46 cases of simple obese before and after acupuncture. Of 46 cases, 39 were of the non-sthenia of liver-Yang (group 1) and 7 of the sthenia of liver-Yang (group 2). It was found that the sympathetic nervous function of the patients in group 1 was markedly higher than the normal. In both of them, the lipid metabolism was abnormal and the content of cAMP in plasma was significantly lower than the normal. The marked effects were achieved on the cases which received one course of treatment (1 month) by acupuncture, the total effective rate being 84.8%. The acupuncture brought about not only antiobesity effect but biphase changes on the blood pressures and Y value as well, that is, acupuncture raised the blood pressures and Y value of the patients in group 1 but reduced the blood pressures and Y value of the patients in group 2. In addition, acupuncture brought about good regulation effect on lipid metabolism and plasma cAMP of patients. This suggests that the regulation effect of acupuncture on plasma cAMP of patients with simple obese might be an important link by which antiobesity effect may be achieved.

Acupuncture Therapy↗
PubMed1990

[Effect of acupuncture and moxibustion on hypothalamus-pituitary-adrenal axis suffering from simple obesity].

In order to understand the effect of acupuncture and moxibustion on hypothalamus-pituitary-adrenal axis in simple obesity, the authors have observed the obese indices, the lipid level, the content of ACTH in plasma and that of salivary cortisol in 39 simple obesity before and after the acupuncture and moxibustion treatment. The results showed that the markedly effective rate was 38.5%, the effective rate was 51.3%, the ineffective rate was 10.3% and the total effective rate was 89.7% after treatment. The results also showed that the function of hypothalamus-pituitary-adrenal axis in simple obesity was lower than that of normal. Acupuncture and moxibustion treatment not only regulated the lipid level and achieved the antiobesity effect but also enhanced the function of hypothalamus-pituitary-adrenal system. The results suggested that the key factor of antiobesity by acupuncture and moxibustion was to increase the function of hypothalamus-pituitary-adrenal system.

Acupuncture Therapy↗
PubMed1990

[Regulatory effects of acupuncture and moxibustion on simple obese complicated with hypertension].

Acupuncture and moxibustion is one of the important therapies in TCM for treating obese. The authors have treated 41 simple obese patients complicated with hypertension by acupuncture and moxibustion which obtained good results. In the treating group, a total effective rate was 87.8% (36 cases). For the purpose of understanding regulatory effect of acupuncture and moxibustion, the authors have observed the obesity indices, the lipid indices (TC, TG, VLDL-C, TC/HDL-C, HDL-C, LDL-C, LDL-C/HDL-C and AI), the physiological indices (saliva secretion, heart rate, respiratory rate, blood pressure and temperature) and the energy metabolism indices (BMR) in the simple obese complicated with hypertension before and after the acupuncture and moxibustion. The results showed that the therapeutic effect of acupuncture and moxibustion could have good results. At the same time, there were the benign regulatory effect of acupuncture and moxibustion in the overeating, the blood pressure, the vegetative nervous indexes, the lipid level and the energy metabolism.

Acupuncture Therapy↗
PubMed1990

[Risk of endogenous N-nitrosodimethylamine formed by dimethylamine in rats--precursors stability].

N-Nitrosodimethylamine (NDMA) is a potential carcinogen and present in our surroundings widely. NDMA can be formed by many precursors, Dimethylamine (DMA) is the most common precursor in food. To evaluate the risk of DMA nitrosation in vivo, so that men can do their best to reduce endogenous nitrosamine exposure, we carried out this research. This paper is the first part of our research. The stabilities of DMA and nitrite in the stomach were studied. DMA was stable and nitrite was decomposed at the speed of second-order reaction. The stabilities of nitrite in simulate gastric acid and in ascorbic (VC) solution also were studied. Nitrite decomposition in simulate gastric acid was very similar to the one in the stomach. VC solution at the equimolar with nitrite can decompose 53-79% of nitrite in one minute with shaking. We suggested that the efficiency of VC inhibiting endogenous nitrosation can be estimated on the basis of decomposing speed of nitrite and nitrosating speed by nitrite.

Animals↗
PubMed1989

Interaction of several nucleoside triphosphate analogues and 10-hydroxycamptothecin with human DNA topoisomerases.

DNA topoisomerase I (Topo I) can exist in several different molecular weight forms in human leukemic cells. The Mr 98,000 form of Topo I was inhibited by several nucleoside triphosphates and their analogues at a 500 microM concentration in the order: dideoxy-GTP greater than 2-bromo-dATP greater than dideoxy-ATP greater than dideoxy-CTP greater than 2-fluoro-dATP greater than 2-chloro-dATP. The same concentration of these nucleoside triphosphates also inhibited the Mr 32,000 and the Mr 35,000 Topo I forms in the order: 2-bromo-dATP greater than dideoxy-GTP greater than 2-fluoro-dATP greater than dideoxy-ATP; however, dideoxy-CTP and 2-chloro-dATP did not inhibit these forms. ATP inhibited both the large and the small molecular weight forms of Topo I at a concentration of 8 mM. DNA topoisomerase II (Topo II) isolated from human leukemic cells requires ATP for its activity. Of the nucleoside triphosphates examined, only dATP could substitute for ATP. In the presence of 500 microM ATP, equimolar concentrations of 2-bromo-dATP, dideoxy-ATP, 2-chloro-dATP, 2-fluoro-dATP, and dideoxy-GTP nucleotide analogues inhibited the unknotting activity of the Topo II enzyme. When the nucleotide analogue concentration was decreased to 250 microM, only 2-bromo-dATP still had a significant inhibitory effect on Topo II. With the exception of 2-bromo-dATP, the analogues studied appeared to inhibit the nicking step of both the Topo I and Topo II enzyme activity. These results differ from previously described mechanisms of inhibition by camptothecin of Topo I and etoposide of Topo II. These enzymatic studies suggest the inhibition of Topo I and Topo II activities could contribute to the cytotoxicity of the respective nucleoside analogues in cell culture, particularly when high concentrations of these nucleoside analogues accumulate as triphosphates inside the cells.

Adenosine Triphosphate↗
PubMed1989

Antitumor agents. 100. Inhibition of human DNA topoisomerase II by cytotoxic ether and ester derivatives of podophyllotoxin and alpha-peltatin.

A principal mechanism of action of the clinical antitumor drugs etoposide (1) and teniposide (2) is the inhibition of catalytic activity of type II DNA topoisomerase and concurrent enzyme-mediated production of lethal DNA strand breaks. Substitution of the glycosidic moiety of 1 or 2 by ester and ethers, as well as the esterification and etherification of alpha-peltatin (4) including its glucosidic ethylidene and thenylidene cyclic acetals (25 and 26), has afforded compounds of much less activity than that of 1. The in vitro cytotoxicity (KB) appears to have no correlation with the inhibitory activity of the human DNA topoisomerase II.

Antineoplastic Agents, Phytogenic↗
PubMed1989

Heterochronic genes control the stage-specific initiation and expression of the dauer larva developmental program in Caenorhabditis elegans.

We report that a stage-specific developmental program, dauer larva formation, is temporally regulated by four heterochronic genes, lin-4, lin-14, lin-28, and lin-29. The effects of mutations in these four genes on dauer larva formation have revealed that they regulate two different processes of dauer larva formation: (1) a decision specifying the larval stage at which dauer larva development initiates, and (2) the specialized differentiation of hypodermal cells during dauer larva morphogenesis. Epistasis analysis has suggested a model in which lin-4 negatively regulates lin-14, and the resulting temporal decrease in lin-14 activity specifies the stage of dauer larva initiation. Our results further suggest that dauer larva morphogenesis by hypodermal cells requires that lin-28 acts to inhibit lin-29 during early larval stages.

Animals↗
PubMed1989

Imaging diagnostic value of myxoma in cardiac chamber. An analysis of 23 cases.

Twenty-three patients with myxoma in the cardiac chamber were analysed from their clinical manifestations and imaging diagnoses. All the patients were confirmed pathologically and 22 of them were further confirmed by operation. In this series, 18 patients had the tumors in the left atria, 3 in the right atria, and 2 in the right ventricles. Diagnosing myxoma by CT and two-dimensional echocardiography was evaluated. The results suggest that to diagnose myxoma in the cardiac chamber, CT is as effective as sonography because it can display clear image, precise location and mobility of the tumor with the flowing blood stream in the cardiac chamber, and provide reliable indications for surgery.

Adolescent↗
PubMed1989

[Imaging diagnosis of intracardiac myxoma (report of 23 cases)].

The diagnostic imaging manifestations of 23 cases of intracardiac myxoma were analyzed, 22 were confirmed by operation and pathology. In this series the myxoma occurred in left atrium in 18 cases, right atrium 3 and right ventricle 2 cases. Evaluation was made on CT and 2-D echocardiography in the diagnosis of intracardiac myxoma, CT as well as sonography can display clearly the contour and location of the tumor and also its motion with blood flow thereby providing reliable evidence for diagnosis and surgery. CT is superior in differentiating intracardiac thrombus and lipoma from myxoma.

Adolescent↗
PubMed1988

Mutagenic and carcinogenic heterocyclic amines in Chinese cooked foods.

Samples of 7 foods commonly eaten in the Northeast of China (i.e. fried and broiled fishes and broiled meat) were tested for mutagenicity on Salmonella typhimurium TA98 with S9 mix. The basic fractions of the samples were mutagenic, inducing 33-2930 revertants/g of cooked food. Fried walleye pollack (a kind of cod fish heated on a stainless steel pan) showed the highest mutagenicity, so attempts were made to isolate mutagens from the basic fraction of this food. The mutagens were purified by treatment with blue cotton and HPLC on a semi-preparative ODS column and analytical cation exchange and ODS columns. 5 mutagens were isolated and identified as 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). 1 g of fried fish was estimated to contain 0.16 ng of IQ, 0.03 ng of MeIQ, 6.44 ng of MeIQx, 0.10 ng of 4,8-DiMeIQx and 69.2 ng of PhIP. MeIQx and PhIP accounted for 24% and 4.7%, respectively, of the total mutagenicity. The other 3 heterocyclic amines were each responsible for only 0.3-1.2% of the total mutagenicity.

China↗
PubMed1987

Studies on DNA topoisomerases I and II in herpes simplex virus type 2-infected cells.

It has been suggested that herpes simplex virus (HSV) type 1 may induce a virus-specific DNA topoisomerase activity which copurifies with virus-induced DNA polymerase. We have examined DNA topoisomerase (TOPO) I and II activities in HSV-2-infected HeLa S3 cells. Both activities were partially purified using DEAE-cellulose, phosphocellulose and double-stranded DNA cellulose column chromatography. It was found that both activities could be separated from HSV-2-specific DNA polymerase. Throughout the purification TOPO I could be immunologically detected with a monoclonal antibody developed against human TOPO I. Regardless of the source, mock- or HSV-2-infected human cells, both types of topoisomerase were equally tolerant of 200 mM-KCl. There appeared to be no apparent heterogeneity of TOPO I in HeLa S3 cells through the course of the HSV-2 infection. We conclude that host cell topoisomerases are quite stable in HSV-2-infected HeLa S3 cells and that there is no evidence that HSV-2 is capable of inducing HSV-2-specific TOPO I and TOPO II activities.

Cell Transformation, Viral↗
PubMed1986

Antitumor agents. 78. Inhibition of human DNA topoisomerase II by podophyllotoxin and alpha-peltatin analogues.

It has been reported that the action of etoposide (VP-16) (14) as an antitumor agent is mediated through its interaction with DNA topoisomerase II which results in DNA breakage inside the cell. In order to understand the mechanism of action as well as structure-activity relationships of 14, several novel, synthetic and some naturally occurring analogues related to podophyllotoxin were examined for inhibition of the DNA topoisomerase II activity. Compound 2 exhibited enhanced activity and compound 5 slightly diminished activity relative to 14. A 4 beta-substituted ether at the C ring and O-demethylation at the E ring appear to enhance activity.

Antineoplastic Agents, Phytogenic↗